Previous Issue
Volume 16, September
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
6.0
3.0
Journals
Micromachines
Volume 16
Issue 10
share announcement

Micromachines, Volume 16, Issue 10 (October 2025) – 101 articles

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
23 pages, 18705 KB  
Review
Electromagnetic Tracking System for Medical Micro Devices: A Review
by Mingshan He, Aoji Zhu and Lidong Yang
Micromachines 2025, 16(10), 1175; https://doi.org/10.3390/mi16101175 - 16 Oct 2025
Abstract
Minimally invasive surgery (MIS) has become increasingly favored by both patients and surgeons owing to its advantages such as shortened recovery times and reduced surgical trauma. To enhance intraoperative feedback from surgical instruments while minimizing harmful radiation exposure, a wide range of electromagnetic [...] Read more.
Minimally invasive surgery (MIS) has become increasingly favored by both patients and surgeons owing to its advantages such as shortened recovery times and reduced surgical trauma. To enhance intraoperative feedback from surgical instruments while minimizing harmful radiation exposure, a wide range of electromagnetic tracking systems (EMTS) has been developed at micro scales for medical applications. This review provides a comprehensive summary of advances in the field over the past five years, with an emphasis on the working principles of EMTS, system architecture, current research progress, and clinical applications. In comparison to other review papers, this article focuses specifically on EMTS for medical micro-devices, such as robotic catheters, endoscopes, and capsule robots. Moreover, Representative research studies and commercial systems are presented along with their clinical implementations, placing greater emphasis on the translation of EMTS into medical applications. Finally, this review outlines and discusses future research directions, highlighting major challenges and potential opportunities for advancing the integration of EMTS into routine clinical workflows. Full article
(This article belongs to the Special Issue Design and Real Time Implementation of Intelligent Control Schemes for Actuators)
►▼ Show Figures

Figure 1

47 pages, 19308 KB  
Review
Research Progress of Electrochemical Machining Technology in Surface Processing: A Review
by Yiran Wang, Yong Yang, Chaoyang Han, Guibing Pang, Shuangjiao Fan, Yunchao Xu, Zhen He and Jianru Fang
Micromachines 2025, 16(10), 1174; https://doi.org/10.3390/mi16101174 - 16 Oct 2025
Abstract
Traditional mechanical processing techniques are confronted with significant challenges when machining advanced materials possessing excellent mechanical properties. Electrochemical machining (ECM), as a material removal technology based on the principle of anodic dissolution, demonstrates distinctive advantages including the absence of contact stress, independence from [...] Read more.
Traditional mechanical processing techniques are confronted with significant challenges when machining advanced materials possessing excellent mechanical properties. Electrochemical machining (ECM), as a material removal technology based on the principle of anodic dissolution, demonstrates distinctive advantages including the absence of contact stress, independence from material hardness, and elimination of mechanical residual stress and recast layers. These characteristics render ECM particularly suitable for high-precision applications requiring superior surface quality. This review systematically summarizes the applications, recent progress, and current challenges of ECM in surface processing. According to diverse surface requirements, ECM technology is classified into two core directions based on primary objectives. The first direction focuses on surface quality enhancement, where nanoscale planarization, residual stress reduction, and uniform surface performance are achieved through precise regulation of anodic dissolution. The second direction concerns material shaping, which is subdivided into macro-scale and micro-scale processing. Macro-scale forming combines electrochemical dissolution with mechanical action to maintain high material removal rate (MRR) while achieving micron-level precision. Micro-scale forming employs nanosecond pulse power supplies and precision electrode/mask designs to overcome manufacturing limitations of micro-nano features on hard-brittle materials. Despite progress achieved, key technical bottlenecks persist, including unstable dynamic control of the inter-electrode gap, environmental concerns regarding electrolytes, and tooling degradation. Future research should prioritize the development of green processing technologies, intelligent control systems, multi-scale manufacturing strategies, and multi-energy field hybrid technologies to enhance the capability of ECM in meeting increasingly stringent surface requirements for advanced materials. Full article
(This article belongs to the Section D：Materials and Processing)
►▼ Show Figures

Figure 1

14 pages, 2529 KB  
Article
Effects of Switching on the 2-DEG Channel in Commercial E-Mode GaN-on-Si HEMT
by Roberto Baca-Arroyo
Micromachines 2025, 16(10), 1173; https://doi.org/10.3390/mi16101173 - 16 Oct 2025
Abstract
In this study, the effects of switching on the two-dimensional electron gas (2-DEG) channel in an E-mode GaN-on-Si HEMT are investigated using a GS-065-004-1-L device that is commercially available for educational practice. A practical prototype with a reduced number of components is proposed, [...] Read more.
In this study, the effects of switching on the two-dimensional electron gas (2-DEG) channel in an E-mode GaN-on-Si HEMT are investigated using a GS-065-004-1-L device that is commercially available for educational practice. A practical prototype with a reduced number of components is proposed, with empirical concepts used to explain its predictive performance when a coreless transformer is series-connected to the E-mode GaN-on-Si HEMT for switching-mode conduction. Conduction modes arising at the p-GaN/n-AlGaN/i-GaN heterojunction in accordance with specifications from the manufacturer’s datasheet were validated using a didactic physical-based model dependent on semiconductor parameters of gallium nitride (GaN). Test circuit-examined waveforms were analyzed, which confirmed that the switching conduction mode of the 2-DEG channel is dependent on physical parameters such as switching operating frequency, temperature, low-field electron mobility, and space charge capacitance. Full article
(This article belongs to the Special Issue GaN-Based Materials and Devices: Research and Applications, 2nd Edition)
►▼ Show Figures

Figure 1

14 pages, 3729 KB  
Article
Research on Piezoelectric Guided Wave Frequency Diverse Array-Based Damage Location Method for Thin-Walled Structures
by Changlin Wang, Quanyao Hu and Yongteng Zhong
Micromachines 2025, 16(10), 1172; https://doi.org/10.3390/mi16101172 - 16 Oct 2025
Abstract
Phased array technology can be realized with directional control with fixed beam steering. However, its directionally dependent beam pattern limits the efficiency of suppressing undesirable distance interference. This paper presents a guided wave frequency diverse array-based damage location method for thin-walled structures. Firstly, [...] Read more.
Phased array technology can be realized with directional control with fixed beam steering. However, its directionally dependent beam pattern limits the efficiency of suppressing undesirable distance interference. This paper presents a guided wave frequency diverse array-based damage location method for thin-walled structures. Firstly, a guided wave frequency diverse array signal model is derived with a relatively small frequency increment that can achieve distance–direction two-dimensional focusing. Secondly, three types of receiving arrays, including a monostatic array, following array, and symmetric array, are constructed to achieve the maximum damage-induced signal amplitude. Finally, a two-dimensional multiple signal classification (MUSIC)-based damage location method is applied for damage imaging in thin-walled structures. Simulations on an aluminum plate and the experiments on an epoxy laminate plate demonstrate the validity and effectiveness of the proposed method. Full article
(This article belongs to the Special Issue Ferroelectric Materials for Advanced Devices)
►▼ Show Figures

Figure 1

16 pages, 2574 KB  
Article
Early Warning of AC Salt Fog Flashover on Composite Insulators Using Fiber Bragg Grating Sensing and Visible Arc Images
by Xiaoxiang Wu, Yanpeng Hao, Zijian Wu, Jikai Bi, Haixin Wu and Lei Huang
Micromachines 2025, 16(10), 1171; https://doi.org/10.3390/mi16101171 - 16 Oct 2025
Abstract
External insulation of coastal power grids faces harsh conditions and is highly susceptible to flashover. Currently, technologies for online monitoring and flashover early warning are severely lacking. As a reflective passive sensing device, Fiber Bragg Grating (FBG) enables the monitoring of surface discharge [...] Read more.
External insulation of coastal power grids faces harsh conditions and is highly susceptible to flashover. Currently, technologies for online monitoring and flashover early warning are severely lacking. As a reflective passive sensing device, Fiber Bragg Grating (FBG) enables the monitoring of surface discharge and provides an early warning for flashover on external insulation. A 10 kV fiber-optic composite insulator was developed in this study. A linear relationship between the FBG central wavelength and interfacial temperature was established through temperature calibration experiments. Coastal salt fog conditions were simulated in an artificial fog chamber, where AC pollution flashover tests were performed on the fiber-optic composite insulator. FBG central wavelength and visible images of discharge were synchronously acquired during experimentation. Experimental results indicate that the interfacial locations on FBGs where the temperature increases during flashover coincide with the positions of visible discharge arcs, demonstrating the effectiveness of the monitoring method. A temperature rise rate of 4.88 × 10−2 °C/s was found to trigger flashover warning, while a rate of 4.96 × 10−2 °C/s initiated trip protection. A discharge-region ratio characteristic was proposed for visible discharge images based on highlight area ratio, R-channel deviation, and mean saturation features. This characteristic serves as a flashover warning when its value reaches 46.7%. This study provides a novel research approach for online monitoring and flashover early warning of external insulation in coastal salt fog environments. Full article
►▼ Show Figures

Figure 1

27 pages, 4352 KB  
Review
Energy Storage, Power Management, and Applications of Triboelectric Nanogenerators for Self-Powered Systems: A Review
by Xiong Dien, Nurulazlina Ramli, Tzer Hwai Gilbert Thio, Zhuanqing Yang, Siyu Hu and Xiang He
Micromachines 2025, 16(10), 1170; https://doi.org/10.3390/mi16101170 - 15 Oct 2025
Abstract
Triboelectric nanogenerators (TENGs) have emerged as efficient mechanical-energy harvesters with advantages—simple architectures, broad material compatibility, low cost, and strong environmental tolerance—positioning them as key enablers of self-powered systems. This review synthesizes recent progress in energy-storage interfaces, power management, and system-level integration for TENGs. [...] Read more.
Triboelectric nanogenerators (TENGs) have emerged as efficient mechanical-energy harvesters with advantages—simple architectures, broad material compatibility, low cost, and strong environmental tolerance—positioning them as key enablers of self-powered systems. This review synthesizes recent progress in energy-storage interfaces, power management, and system-level integration for TENGs. We analyze how intrinsic source characteristics—high output voltage, low current, large internal impedance, and pulsed waveforms—complicate efficient charge extraction and utilization. Accordingly, this work highlights a variety of power-conditioning approaches, including advanced rectification, multistage buffering, impedance transformation/matching, and voltage regulation. Moreover, recent developments in the integration of TENGs with storage elements, cover hybrid topologies and flexible architectures. Application case studies in wearable electronics, environmental monitoring, smart-home security, and human–machine interfaces illustrate the dual roles of TENGs as power sources and self-driven sensors. Finally, we outline research priorities: miniaturized and integrated power-management circuits, AI-assisted adaptive control, multimodal hybrid storage platforms, load-adaptive power delivery, and flexible, biocompatible encapsulation. Overall, this review provides a consolidated view of state-of-the-art TENG-based self-powered systems and practical guidance toward real-world deployment. Full article
(This article belongs to the Section A：Physics)
►▼ Show Figures

Figure 1

30 pages, 6656 KB  
Article
A Novel Tool Condition Monitoring Technique of Determining Insert Flank Wear Width of Indexable Face Milling Tools Using On-Machine Laser Tool Setters
by Tao Fang, Zezhong Chen, Haibo Feng, Peng Chen and Zhiyong Chang
Micromachines 2025, 16(10), 1169; https://doi.org/10.3390/mi16101169 - 15 Oct 2025
Abstract
Indexable face milling tools are often used to machine workpieces with large axial and radial depth of cuts, and thus, the inserts quickly wear out in machining. A kernel technique of smart machining is tool wear compensation, which is to regularly and automatically [...] Read more.
Indexable face milling tools are often used to machine workpieces with large axial and radial depth of cuts, and thus, the inserts quickly wear out in machining. A kernel technique of smart machining is tool wear compensation, which is to regularly and automatically measure the insert radius/length with a laser tool setter on the machine table during machining, and compensate them in the subsequent machining. Another technique is tool condition monitoring, which is to calculate the insert flank wear width for tool condition and compare with its threshold. When it is less than but close to its threshold of invalid inserts, the cutting tool is automatically changed right before it becomes invalid. On-machine laser tool setters have been equipped in CNC machine tools for several years; however, they cannot conduct cutting tool condition monitoring. The main reason is that the insert flank wear width cannot be measured on the on-machine laser tool setter, and the status quo is that the cutting tool is replaced either too early or too late. To address this problem, a novel tool condition monitoring technique of determining the insert flank wear width of indexable face milling tool using on-machine laser tool setters is proposed. According to the insert geometry, the worn cutting edge and a new workpiece milling mechanism proposed in this work, the insert flank wear width can be calculated. In machining, the insert radius wear is measured on the on-machine laser tool setter, and the insert flank wear width is calculated to evaluate whether it is invalid soon. The results indicate that the optimal height for radius measurement is located near the intersection of the corner and side edges point MR3, and close to the cutting depth point MR5. A wear land width threshold of 0.10 mm is established to define tool failure. The proposed calculation method achieves high accuracy, maintaining calculation errors within 14.00%. The inserts can be used in good condition with the maximum lifespan. This method has been verified in machining applications and can be directly applied in industry. Full article
(This article belongs to the Special Issue Advanced Micro- and Nano-Manufacturing Technologies, 2nd Edition)
►▼ Show Figures

Figure 1

15 pages, 3635 KB  
Article
Development and Comparative Evaluation of Two Enzyme-Based Amperometric Biosensor Designs for Alanine Aminotransferase Determination in Biological Fluids
by Daryna Mruga, Yevhen Vakhovskyi, Veronika Bakhmat, Viktoriya Pyeshkova, Sergii Dzyadevych and Oleksandr Soldatkin
Micromachines 2025, 16(10), 1168; https://doi.org/10.3390/mi16101168 - 15 Oct 2025
Abstract
Alanine aminotransferase (ALT) is a key biomarker of liver function. Compared with conventional assays for ALT detection—which are expensive, time-consuming, labor-intensive, and require experienced personnel—biosensors represent a promising alternative, but it remains unclear which biorecognitive enzymatic configuration offers the best analytical performance for [...] Read more.
Alanine aminotransferase (ALT) is a key biomarker of liver function. Compared with conventional assays for ALT detection—which are expensive, time-consuming, labor-intensive, and require experienced personnel—biosensors represent a promising alternative, but it remains unclear which biorecognitive enzymatic configuration offers the best analytical performance for ALT detection. This study presents the development and comparative evaluation of two amperometric biosensors based on oxidase biorecognition elements: pyruvate oxidase (POx) and glutamate oxidase (GlOx). Enzymes were immobilized onto platinum electrodes under optimized conditions using entrapment for POx (pH 7.4, enzyme loading 1.62 U/µL, PVA-SbQ concentration 13.2%) and covalent crosslinking for GlOx (pH 6.5, enzyme loading 2.67%, glutaraldehyde concentration 0.3%). Analytical parameters were systematically assessed, including linear range (1–500 U/L for POx vs. 5–500 U/L for GlOx), limit of detection (1 U/L for both), and sensitivity (0.75 vs. 0.49 nA/min at 100 U/L). The POx-based biosensor demonstrated higher sensitivity and lower detection limits, whereas the GlOx-based biosensor exhibited greater stability in complex solutions and reduced assay costs due to a simpler working solution. Moreover, while the POx-based system is uniquely suited for ALT determination, the GlOx-based sensor can be affected by AST activity in samples but may also be adapted for targeted AST detection. Overall, the study highlights a trade-off between sensitivity, robustness, and versatility in ALT biosensor design, providing guidance for the rational development of clinically relevant devices. Full article
(This article belongs to the Special Issue Recent Progress in Biosensors for Clinical Diagnostics, Food Quality Control, and Environmental Monitoring)
►▼ Show Figures

Figure 1

18 pages, 9735 KB  
Article
Machining Accurate Deep Curved Forms on Tungsten Carbide–Cobalt (WC-Co) Eliminating Tool Wear in the Electrical Discharge Turning Operation
by Mohammadjafar Hadad, Mehdi Soleymani and Amir Alinaghizadeh
Micromachines 2025, 16(10), 1167; https://doi.org/10.3390/mi16101167 - 15 Oct 2025
Abstract
Machining hard metals presents various challenges, especially with materials like WC-Co, known for their exceptional hardness and wear resistance, making them ideal for cutting tools. Among machining methods, Electrical Discharge Machining (EDM) stands out for its ability to machine hard materials with no [...] Read more.
Machining hard metals presents various challenges, especially with materials like WC-Co, known for their exceptional hardness and wear resistance, making them ideal for cutting tools. Among machining methods, Electrical Discharge Machining (EDM) stands out for its ability to machine hard materials with no mechanical damage, which is critical for machining fragile components. For form shape machining symmetrical parts like WC-Co bars, electrical discharge turning (EDT) could be applied. Despite its potential, limited research exists on deep form turning of hard metals like WC-Co using EDT. This study addresses that gap by comparing the final geometrical outcomes of two EDT setups: vertical and horizontal tool electrode configurations. Additionally, the impact of workpiece rotational speed on surface quality was examined. Results showed that the vertical tool electrode setup produced more accurate geometries and smoother surfaces. Furthermore, increasing the workpiece’s rotational speed improved flushing efficiency, resulting in reduced surface roughness and a cleaner machined surface. Full article
(This article belongs to the Special Issue Future Prospects of Additive Manufacturing)
►▼ Show Figures

Figure 1

13 pages, 3442 KB  
Article
Patterning Fidelity Enhancement and Aberration Mitigation in EUV Lithography Through Source–Mask Optimization
by Qi Wang, Qiang Wu, Ying Li, Xianhe Liu and Yanli Li
Micromachines 2025, 16(10), 1166; https://doi.org/10.3390/mi16101166 - 14 Oct 2025
Abstract
Extreme ultraviolet (EUV) lithography faces critical challenges in aberration control and patterning fidelity as technology nodes shrink below 3 nm. This work demonstrates how Source–Mask Optimization (SMO) simultaneously addresses both illumination and mask design to enhance pattern transfer accuracy and mitigate aberrations. Through [...] Read more.
Extreme ultraviolet (EUV) lithography faces critical challenges in aberration control and patterning fidelity as technology nodes shrink below 3 nm. This work demonstrates how Source–Mask Optimization (SMO) simultaneously addresses both illumination and mask design to enhance pattern transfer accuracy and mitigate aberrations. Through a comprehensive optimization framework incorporating key process metrics, including critical dimension (CD), exposure latitude (EL), and mask error factor (MEF), we achieve significant improvements in imaging quality and process window for 40 nm minimum pitch patterns, representative of 2 nm node back-end-of-line (BEOL) requirements. Our analysis reveals that intelligent SMO implementation not only enables robust patterning solutions but also compensates for inherent EUV aberrations by balancing source characteristics with mask modifications. On average, our results show a 4.02% reduction in CD uniformity variation, concurrent with a 1.48% improvement in exposure latitude and a 5.45% reduction in MEF. The proposed methodology provides actionable insights for aberration-aware SMO strategies, offering a pathway to maintain lithographic performance as feature sizes continue to scale. These results underscore SMO’s indispensable role in advancing EUV lithography capabilities for next-generation semiconductor manufacturing. Full article
(This article belongs to the Special Issue Recent Advances in Lithography)
►▼ Show Figures

Figure 1

21 pages, 7655 KB  
Article
Enhancing the Machinability of Sapphire via Ion Implantation and Laser-Assisted Diamond Machining
by Jinyang Ke, Honglei Mo, Ke Ling, Jianning Chu, Xiao Chen and Jianfeng Xu
Micromachines 2025, 16(10), 1165; https://doi.org/10.3390/mi16101165 - 14 Oct 2025
Abstract
Sapphire crystals, owing to their outstanding mechanical and optical properties, which are widely used in advanced optics, microelectronic devices, and medical instruments. The manufacturing precision of sapphire optical components critically affects the performance of advanced optical systems. However, the extremely high hardness and [...] Read more.
Sapphire crystals, owing to their outstanding mechanical and optical properties, which are widely used in advanced optics, microelectronic devices, and medical instruments. The manufacturing precision of sapphire optical components critically affects the performance of advanced optical systems. However, the extremely high hardness and low fracture toughness of sapphire make it a typical hard-to-machine material, prone to brittle surface fractures and subsurface damage during material removal. Improving the machinability of sapphire remains a pressing challenge in advanced manufacturing. In this study, surface modification and enhanced ductility of C-plane sapphire were achieved via ion implantation, and the machinability of the modified sapphire was further improved through laser-assisted diamond machining (LADM). Monte Carlo simulations were employed to investigate the interaction mechanisms between incident ions and the target material. Based on the simulation results, phosphorus ion implantation experiments were conducted, and transmission electron microscopy observation was used to characterize the microstructural evolution of the modified layer, while the optical properties of the samples before and after modification were analyzed. Finally, groove cutting experiments verified the enhancement in ductile machinability of the modified sapphire under LADM. At a laser power of 16 W, the ductile–brittle transition depth of the modified sapphire increased to 450.67 nm, representing a 51.57% improvement over conventional cutting. The findings of this study provide valuable insights for improving the ductile machining performance of hard and brittle materials. Full article
(This article belongs to the Special Issue Future Trends in Ultra-Precision Machining)
►▼ Show Figures

Figure 1

15 pages, 8984 KB  
Article
Sintering for High Power Optoelectronic Devices
by Hannes Schwan, Nihesh Mohan, Maximilian Schmid, Rocky Kumar Saha, Holger Klassen, Klaus Müller and Gordon Elger
Micromachines 2025, 16(10), 1164; https://doi.org/10.3390/mi16101164 - 14 Oct 2025
Abstract
Residual-free eutectic Au80Sn20 soldering is still the dominant assembly technology for optoelectronic devices such as high-power lasers, LEDs, and photodiodes. Due to the high cost of gold, alternatives are desirable. This paper investigates the thermal performance of copper-based sintering for optoelectronic submodules on [...] Read more.
Residual-free eutectic Au80Sn20 soldering is still the dominant assembly technology for optoelectronic devices such as high-power lasers, LEDs, and photodiodes. Due to the high cost of gold, alternatives are desirable. This paper investigates the thermal performance of copper-based sintering for optoelectronic submodules on first and second level to obtain thermally efficient thin bondlines. Sintered interconnects obtained by a new particle-free copper ink, based on complexed copper salt, are compared with copper flake and silver nanoparticle sintered interconnects and benchmarked against AuSn solder interconnects. The copper ink is dispensed and predried at 130 °C to facilitate in situ generation of Cu nanoparticles by thermal decomposition of the metal salt before sintering. Submounts are then sintered at 275 °C for 15 min under nitrogen with 30 MPa pressure, forming uniform 2–5 µm copper layers achieving shear strengths above 31 MPa. Unpackaged LEDs are bonded on first level using the copper ink but applying only 10 MPa to avoid damaging the semiconductor dies. Thermal performance is evaluated via transient thermal analysis. Results show that copper ink interfaces approach the performance of thin AuSn joints and match silver interconnects at second level. However, at first level, AuSn and sintered interconnects of commercial silver and copper pastes remained superior due to the relative inhomogeneous thickness of the thin Cu copper layer after predrying, requiring higher bonding pressure to equalize surface inhomogeneities. Full article
(This article belongs to the Special Issue Emerging Trends in Optoelectronic Device Engineering)
►▼ Show Figures

Figure 1

17 pages, 5096 KB  
Article
Numerical Simulation and Experimental Study on Picosecond Laser Polishing of 4H-SiC Wafer
by Yixiong Yan, Yuxuan Cheng, Sijia Chen, Yu Tang, Fan Zhang and Piaopiao Gao
Micromachines 2025, 16(10), 1163; https://doi.org/10.3390/mi16101163 - 14 Oct 2025
Viewed by 52
Abstract
4H-SiC wafers usually require polishing treatment after slicing to improve the surface quality. However, traditional polishing processes have problems such as low removal efficiency and easy surface damage, which affect the reliability of electronic devices. In this paper, picosecond laser polishing technology is [...] Read more.
4H-SiC wafers usually require polishing treatment after slicing to improve the surface quality. However, traditional polishing processes have problems such as low removal efficiency and easy surface damage, which affect the reliability of electronic devices. In this paper, picosecond laser polishing technology is used to study the 4H-SiC wafers after slicing. Numerical models of single-pulse ablation and moving heat source polishing were established to reveal the interaction mechanism between laser and material, including the dynamic evolution of free electron density and the remarkable spatiotemporal non-equilibrium heat transfer characteristics of the electron–lattice system. The sliced 4H-SiC surface with a roughness of 2265 nm was polished by a 1064 nm picosecond laser, and the influence of laser power and scanning speed on the surface quality was systematically studied. By collaboratively optimizing the polishing power and speed, the surface roughness of the sample can be significantly reduced to 207.33 nm (a decrease of 90.85%). The research results indicate that an ultrafast laser is suitable for the pretreatment process of sliced silicon carbide wafers, laying a foundation for further research in the future. This research has a certain research significance for promoting the development of ultrafast laser polishing technology for single crystal silicon carbide wafers and improving the performance and reliability of semiconductor devices. Full article
►▼ Show Figures

Figure 1

23 pages, 2493 KB  
Article
EAAUnet-ILT: A Lightweight and Iterative Mask Optimization Resolution with SRAF Constraint Scheme
by Ke Wang and Kun Ren
Micromachines 2025, 16(10), 1162; https://doi.org/10.3390/mi16101162 - 14 Oct 2025
Viewed by 98
Abstract
With the continuous scaling-down of integrated circuit feature sizes, inverse lithography technology (ILT), as the most groundbreaking resolution enhancement technique (RET), has become crucial in advanced semiconductor manufacturing. By directly optimizing mask patterns through inverse computation rather than rule-based local corrections, ILT can [...] Read more.
With the continuous scaling-down of integrated circuit feature sizes, inverse lithography technology (ILT), as the most groundbreaking resolution enhancement technique (RET), has become crucial in advanced semiconductor manufacturing. By directly optimizing mask patterns through inverse computation rather than rule-based local corrections, ILT can more accurately approximate target design patterns while extending the process window. However, current mainstream ILT approaches—whether machine learning-based or gradient descent-based—all face the challenge of balancing mask optimization quality and computational time. Moreover, ILT often faces a trade-off between imaging fidelity and manufacturability; fidelity-prioritized optimization leads to explosive growth in mask complexity, whereas manufacturability constraints require compromising fidelity. To address these challenges, we propose an iterative deep learning-based ILT framework incorporating a lightweight model, ghost and adaptive attention U-net (EAAUnet) to accelerate runtime and reduce computational overhead while progressively improving mask quality through multiple iterations based on the pre-trained network model. Compared to recent state-of-the-art (SOTA) ILT solutions, our approach achieves up to a 39% improvement in mask quality metrics. Additionally, we introduce a mask constraint scheme to regulate complex SRAF (sub-resolution assist feature) patterns on the mask, effectively reducing manufacturing complexity. Full article
(This article belongs to the Special Issue Recent Advances in Lithography)
►▼ Show Figures

Figure 1

3 pages, 705 KB  
Correction
Correction: Wang et al. Temperature Effects in Packaged RF MEMS Switches with Optimized Gold Electroplating Process. Micromachines 2024, 15, 1085
by Lifeng Wang, Lili Jiang, Ning Ma and Xiaodong Huang
Micromachines 2025, 16(10), 1161; https://doi.org/10.3390/mi16101161 - 14 Oct 2025
Viewed by 51
Abstract
It was found that the temperature control of the electroplating station in the previously published paper [...] Full article
►▼ Show Figures

Figure 2

17 pages, 3651 KB  
Article
Optofluidic Lens Refractometer
by Yifan Zhang, Qi Wang, Yuxiang Li, Junjie Liu, Ziyue Lin, Mingkai Fan, Yichi Zhang and Xiang Wu
Micromachines 2025, 16(10), 1160; https://doi.org/10.3390/mi16101160 - 13 Oct 2025
Viewed by 190
Abstract
In the face of increasingly severe global environmental challenges, the development of low-cost, high-precision, and easily integrable environmental monitoring sensors is of paramount importance. Existing optical refractive index sensors are often limited in application due to their complex structures and high costs, or [...] Read more.
In the face of increasingly severe global environmental challenges, the development of low-cost, high-precision, and easily integrable environmental monitoring sensors is of paramount importance. Existing optical refractive index sensors are often limited in application due to their complex structures and high costs, or their bulky size and difficulty in automation. This paper proposes a novel optical microfluidic refractometer, consisting solely of a laser source, an optical microfluidic lens, and a CCD detector. Through an innovative “simple structure + algorithm” design, the sensor achieves high-precision measurement while significantly reducing cost and size and enhancing robustness. With the aid of signal processing algorithms, the device currently enables the detection of refractive index gradients as low as 1.4 × 10−5 within a refractive index range of 1.33 to 1.48. Full article
(This article belongs to the Special Issue Optofluidic Devices and Their Applications)
►▼ Show Figures

Figure 1

15 pages, 1187 KB  
Review
Integration of Point-of-Care Technology in the Decoding Process of Single Nucleotide Polymorphism for Healthcare Application †
by Thi Ngoc Diep Trinh, Hanh An Nguyen, Nguyen Pham Anh Thi, Thi Xuan Tuy Ho, Kieu The Loan Trinh and Nguyen Khoi Song Tran
Micromachines 2025, 16(10), 1159; https://doi.org/10.3390/mi16101159 - 13 Oct 2025
Viewed by 196
Abstract
Single nucleotide polymorphism (SNP) involves plenty of genetic disorders in organisms that can be passed down to the next generation or cause the stimulant signal that leads to early mortality in infants, especially within humankind. In medical field, real-time polymerase chain reaction (RT-PCR) [...] Read more.
Single nucleotide polymorphism (SNP) involves plenty of genetic disorders in organisms that can be passed down to the next generation or cause the stimulant signal that leads to early mortality in infants, especially within humankind. In medical field, real-time polymerase chain reaction (RT-PCR) is the most popular method for disease diagnosis. The investigation of genetic maps for the prediction of inherited illnesses needs the collaboration of sequencing technique and genome analysis. Although these methods are popular now, the cost for each test is quite high. Moreover, there is the requirement of extra machines and skillful technician or specialist level. Among these popular methods, the allele-specific polymerase chain reaction (AS-PCR), allele-specific loop isothermal mediated amplification (AS-LAMP), and allele-specific recombinase polymerase amplification (AS-RPA) are brought up for screening the nucleotide differences in the genetic sequence which will be noticed in this review as their availability, novelty, and potential for quick distinguishing of disease caused by SNP. Point-of-care testing (POCT) is a system built in a portable size but can perform the entire process of SNP recognition. Along with that, the POCT is intersected with the mentioned amplification methods and the genetic material preparation steps to become a united framework for higher efficiency and accuracy and lower cost. According to that, this review will focus on three common amplification techniques and their combination with POCT in the upstream and downstream process to genotype SNP related to human diseases. Full article
(This article belongs to the Section B4: Point-of-Care Devices)
►▼ Show Figures

Figure 1

34 pages, 4932 KB  
Review
Recent Progress in Liquid Microlenses and Their Arrays for Adaptive and Applied Optical Systems
by Siyu Lu, Zheyuan Cao, Jinzhong Ling, Ying Yuan, Xin Liu, Xiaorui Wang and Jin-Kun Guo
Micromachines 2025, 16(10), 1158; https://doi.org/10.3390/mi16101158 - 13 Oct 2025
Viewed by 334
Abstract
Liquid microlenses and their arrays (LMLAs) have emerged as a transformative platform in adaptive optics, offering superior reconfigurability, compactness, and fast response compared to conventional solid-state lenses. This review summarizes recent progress from an application-oriented perspective, focusing on actuation mechanisms, fabrication strategies, and [...] Read more.
Liquid microlenses and their arrays (LMLAs) have emerged as a transformative platform in adaptive optics, offering superior reconfigurability, compactness, and fast response compared to conventional solid-state lenses. This review summarizes recent progress from an application-oriented perspective, focusing on actuation mechanisms, fabrication strategies, and functional performance. Among actuation mechanisms, electric-field-driven approaches are highlighted, including electrowetting for shape tuning and liquid crystal-based refractive-index tuning techniques. The former excels in tuning range and response speed, whereas the latter enables programmable wavefront control with lower optical aberrations but limited efficiency. Notably, double-emulsion configurations, with fast interfacial actuation and inherent structural stability, demonstrate great potential for highly integrated optical components. Fabrication methodologies—including semiconductor-derived processes, additive manufacturing, and dynamic molding—are evaluated, revealing trade-offs among scalability, structural complexity, and cost. Functionally, advances in focal length tuning, field-of-view expansion, depth-of-field extension, and aberration correction have been achieved, though strong coupling among these parameters still constrains system-level performance. Looking forward, innovations in functional materials, hybrid fabrication, and computational imaging are expected to mitigate these constraints. These developments will accelerate applications in microscopy, endoscopy, AR/VR displays, industrial inspection, and machine vision, while paving the way for intelligent photonic systems that integrate adaptive optics with machine learning for real-time control. Full article
(This article belongs to the Special Issue Micro-Nano Photonics: From Design and Fabrication to Application)
►▼ Show Figures

Figure 1

12 pages, 1654 KB  
Article
Research on Open Magnetic Shielding Packaging for STT and SOT-MRAM
by Haibo Ye, Xiaofei Zhang, Nannan Lu, Jiawei Li, Jun Jia, Guilin Zhao, Jiejie Sun, Lei Zhang and Chao Wang
Micromachines 2025, 16(10), 1157; https://doi.org/10.3390/mi16101157 - 13 Oct 2025
Viewed by 303
Abstract
As an emerging type of non-volatile memory, magneto-resistive random access memory (MRAM) stands out for its exceptional reliability and rapid read–write speeds, thereby garnering considerable attention within the industry. The memory cell architecture of MRAM is centered around the magnetic tunnel junction (MTJ), [...] Read more.
As an emerging type of non-volatile memory, magneto-resistive random access memory (MRAM) stands out for its exceptional reliability and rapid read–write speeds, thereby garnering considerable attention within the industry. The memory cell architecture of MRAM is centered around the magnetic tunnel junction (MTJ), which, however, is prone to interference from external magnetic fields—a limitation that restricts its application in demanding environments. To address this challenge, we propose an innovative open magnetic shielding structure. This design demonstrates remarkable shielding efficacy against both in-plane and perpendicular magnetic fields, effectively catering to the magnetic shielding demands of both spin-transfer torque (STT) and spin–orbit torque (SOT) MRAM. Finite element magnetic simulations reveal that when subjected to an in-plane magnetic field of 40 mT, the magnetic field intensity at the chip level is reduced to nearly 1‰ of its original value. Similarly, under a perpendicular magnetic field of 40 mT, the magnetic field at the chip is reduced to 2‰ of its initial strength. Such reductions significantly enhance the anti-magnetic capabilities of MRAM. Moreover, the magnetic shielding performance remains unaffected by the height of the packaging structure, ensuring compatibility with various chip stack packaging requirements across different layers. The research presented in this paper holds immense significance for the realization of highly reliable magnetic shielding packaging solutions for MRAM. Full article
►▼ Show Figures

Figure 1

17 pages, 3320 KB  
Article
Research on Optimizing Forming Accuracy in Food 3D Printing Based on Temperature–Pressure Dual Closed-Loop Control
by Junhua Wang, Hao Cao, Jianan Shen, Xu Duan, Yanwei Xu, Tancheng Xie and Ruijie Gu
Micromachines 2025, 16(10), 1156; https://doi.org/10.3390/mi16101156 - 12 Oct 2025
Viewed by 323
Abstract
In this paper, a new 3D printing system based on temperature–pressure double closed-loop collaborative control is proposed to solve the problem of 3D printing accuracy of starch food. The rapid and accurate adjustment of the nozzle temperature is realized by the hybrid control [...] Read more.
In this paper, a new 3D printing system based on temperature–pressure double closed-loop collaborative control is proposed to solve the problem of 3D printing accuracy of starch food. The rapid and accurate adjustment of the nozzle temperature is realized by the hybrid control of Bang-Bang and PID, and the extrusion pressure is optimized in real time by combining the adaptive fuzzy PID algorithm, which effectively reduces the influence from the change of material rheological properties and external interference. The experimental results show that the printing accuracy of the system is up to 98% at 40 °C, the pressure fluctuation is reduced by 80%, and the molding accuracy of complex structures is improved to 97%, which significantly improves the over-extrusion and under-extrusion, and provides an effective solution for stable and high-precision printing of high-viscosity food materials. Full article
(This article belongs to the Special Issue Advanced Micro- and Nano-Manufacturing Technologies, 2nd Edition)
►▼ Show Figures

Figure 1

15 pages, 5525 KB  
Article
Post Wire-Bonding Corrosion Prevention Strategies to Mitigate Chloride- and Bromide-Induced Corrosion Failures in Cu- and PCC-Based Wire-Bonded Packages
by Dinesh Kumar Kumaravel, Shinoj Sridharan Nair, Khanh Tuyet Anh Tran, Pavan Ahluwalia, Kevin Antony Jesu Durai and Oliver Chyan
Micromachines 2025, 16(10), 1155; https://doi.org/10.3390/mi16101155 - 12 Oct 2025
Viewed by 239
Abstract
To ensure the highest safety standards in modern automobiles, the industry is constantly adopting zero-defect frameworks, such as AEC-Q100, which aims for defective-parts-per-billion (DPPB) or grade-0 level reliability standards in automotive integrated-circuit (IC) packages. Most contemporary wire-bonded packages use either pure copper (Cu) [...] Read more.
To ensure the highest safety standards in modern automobiles, the industry is constantly adopting zero-defect frameworks, such as AEC-Q100, which aims for defective-parts-per-billion (DPPB) or grade-0 level reliability standards in automotive integrated-circuit (IC) packages. Most contemporary wire-bonded packages use either pure copper (Cu) or palladium (Pd)-coated copper (PCC) wires bonded to aluminum (Al) bond pads as interconnections. This choice is made due to their lower cost and superior electrical and mechanical performance, compared to traditional gold wire-based devices. However, these Cu–Al wire-bonded interconnections are prone to ion-induced lift-off/open-circuit corrosion failures when exposed to even trace amounts (<20 ppm) of extrinsic and/or intrinsic halide (Cl− and Br−) contaminants, decreasing device longevity. This study investigates corrosion failure mechanisms in Cu and PCC wire-based devices by subjecting non-encapsulated devices to a highly accelerated aqueous-immersion screening test containing 100 ppm chloride (Cl−), 100 ppm bromide (Br−), and a mixed-ion solution (MX: Cl− + Br−). The screening results indicate that even control PCC-Al devices with a Pd overlayer can be susceptible to Cl− and Br− induced corrosion, with 21 ± 1.6% lift-off failures in MX-solution. In contrast, applying a novel Cu-selective passivation reduced lift-off to 3.3 ± 0.6% and introducing phosphonic-acid-based inhibitor into the MX solution eliminated lift-off failures, demonstrating markedly improved reliability. Full article
(This article belongs to the Special Issue Microelectronics Assembly and Packaging: Materials and Technologies, 2nd Edition)
►▼ Show Figures

Figure 1

14 pages, 6040 KB  
Article
Analysis of Key Factors Affecting the Sensitivity of Dual-Backplate Capacitive MEMS Microphones
by Chengpu Sun, Haosheng Liu, Ludi Kang and Bilong Liu
Micromachines 2025, 16(10), 1154; https://doi.org/10.3390/mi16101154 - 12 Oct 2025
Viewed by 213
Abstract
This paper presents a comprehensive investigation of sensitivity-determining factors in dual-backplate capacitive MEMS microphones through analytical modeling, finite element analysis (FEM), and experimental validation. The study focuses on three critical design parameters: backplate perforation density, membrane tension, and electrode gap spacing. A lumped [...] Read more.
This paper presents a comprehensive investigation of sensitivity-determining factors in dual-backplate capacitive MEMS microphones through analytical modeling, finite element analysis (FEM), and experimental validation. The study focuses on three critical design parameters: backplate perforation density, membrane tension, and electrode gap spacing. A lumped parameter model (LPM) and FEM simulations are employed to characterize the dynamic behavior and frequency response of the microphone. Simulation results demonstrate that reducing the backplate hole diameter or hole count amplifies squeeze-film damping, inducing nonlinear effects and anti-resonance dips near the fundamental frequency (f0) while mitigating low-frequency roll-off (<100 Hz). Membrane tension exhibits a nonlinear relationship with sensitivity, stabilizing at high tension (>7000 N/m) but risking pull-in instability at low tension (<1500 N/m). Smaller electrode gaps enhance sensitivity but are constrained by pull-in voltage limitations. The FEM model achieves higher accuracy (≤2 dB error) than LPM in predicting low-frequency response anomalies. This work provides systematic guidelines for optimizing dual-backplate MEMS microphone designs, balancing sensitivity, stability, and manufacturability. Full article
►▼ Show Figures

Figure 1

13 pages, 5799 KB  
Article
Additive Manufacturing of Gear Electrodes and EDM of a Gear Cavity
by Kai Jiang, Yangquan Liu, Bin Xu, Shunda Zhan and Junwei Liang
Micromachines 2025, 16(10), 1153; https://doi.org/10.3390/mi16101153 - 11 Oct 2025
Viewed by 188
Abstract
Plastic gears are used in a variety of industrial fields and are primarily produced by injection molding with a gear cavity. At present, EDM is usually used for machining gear cavities with metal materials, and the tool electrode used in the process is [...] Read more.
Plastic gears are used in a variety of industrial fields and are primarily produced by injection molding with a gear cavity. At present, EDM is usually used for machining gear cavities with metal materials, and the tool electrode used in the process is usually machined through a milling process. For helical gear cavities and helical bevel gear cavities, certain problems are encountered when the tool electrodes of EDM are obtained from milling procedures, including waste of raw materials and the complex technical process. Focusing on the above problems, this paper used copper powder to fabricate gear electrodes through a selective laser sintering process. The obtained gear electrodes underwent heat treatment and the effects of the main process parameters on the electrical conductance of tool electrodes were analyzed in this study. Finally, the heat-treated gear electrodes were applied to EDM to fabricate a helical gear cavity and a helical bevel gear cavity. During EDM, the TWR and MRR of the gear electrodes were 0.0029 mm3/min and 0.3872 mm3/min, respectively. Compared with that of gear electrodes made by the milling process, the MRR of the gear electrodes fabricated by SLS improved by 31.53%. Full article
(This article belongs to the Special Issue Micro-Manufacturing and Applications, 5th Edition: Materials and High-Precision Micromachining)
►▼ Show Figures

Figure 1

33 pages, 3122 KB  
Review
Thermal Side-Channel Threats in Densely Integrated Microarchitectures: A Comprehensive Review for Cyber–Physical System Security
by Amrou Zyad Benelhaouare, Idir Mellal, Michel Saydé, Gabriela Nicolescu and Ahmed Lakhssassi
Micromachines 2025, 16(10), 1152; https://doi.org/10.3390/mi16101152 - 11 Oct 2025
Viewed by 541
Abstract
Densely integrated microarchitectures spanning three-dimensional integrated circuits (3D-ICs), chiplet-based designs, and system-in-package (SiP) assemblies make heat a first-order security concern rather than a mere reliability issue. This review consolidates the landscape of thermal side-channel attacks (TSCAs) on densely integrated microarchitectures: we systematize observation [...] Read more.
Densely integrated microarchitectures spanning three-dimensional integrated circuits (3D-ICs), chiplet-based designs, and system-in-package (SiP) assemblies make heat a first-order security concern rather than a mere reliability issue. This review consolidates the landscape of thermal side-channel attacks (TSCAs) on densely integrated microarchitectures: we systematize observation vectors and threat models, clarify core concepts and assumptions, compare the most credible evidence from the past decade, and distill the main classes of defenses across the hardware–software stack. We also explain why hardening against thermal leakage is integral to cyber–physical system (CPS) security and outline the most promising research directions for the field. The strategic relevance of this agenda is reflected in current policy and funding momentum, including initiatives by the United States Department of Homeland Security and the Cybersecurity and Infrastructure Security Agency (DHS/CISA) on operational technology (OT) security, programs by the National Science Foundation (NSF) on CPS, and Canada’s Regional Artificial Intelligence Initiative and Cyber-Physical Resilience Program (RAII, >CAD 35 million), to bridge advanced microelectronics with next-generation cybersecurity. This survey offers a clear, high-level map of the problem space and a focused baseline for future work. Full article
(This article belongs to the Special Issue Microelectronics Assembly and Packaging: Materials and Technologies, 2nd Edition)
►▼ Show Figures

Figure 1

14 pages, 4357 KB  
Article
Thermal Gas Flow Sensor Using SiGe HBT Oscillators Based on GaN/Si SAW Resonators
by Wenpu Cui, Jie Cui, Wenchao Zhang, Guofang Yu, Di Zhao, Jingqing Du, Zhen Li, Jun Fu and Tianling Ren
Micromachines 2025, 16(10), 1151; https://doi.org/10.3390/mi16101151 - 10 Oct 2025
Viewed by 209
Abstract
This paper presents a thermal gas flow sensing system, from surface acoustic wave (SAW) temperature sensor to oscillation circuit and multi-module miniaturization integration. A single-port GaN/Si SAW resonator with single resonant mode and excellent characteristics was fabricated. Combined with an in-house-developed SiGe HBT, [...] Read more.
This paper presents a thermal gas flow sensing system, from surface acoustic wave (SAW) temperature sensor to oscillation circuit and multi-module miniaturization integration. A single-port GaN/Si SAW resonator with single resonant mode and excellent characteristics was fabricated. Combined with an in-house-developed SiGe HBT, a temperature-sensitive high-frequency oscillator was constructed. Under constant temperature control, system-level flow measurement was achieved through dual-oscillation configuration and modular integration. The fabricated SAW device shows a temperature coefficient of frequency (TCF) −28.29 ppm/K and temperature linearity 0.998. The oscillator operates at 1.91 GHz with phase noise of −97.72/−118.62 dBc/Hz at 10/100 kHz offsets. The system demonstrates excellent dynamic response and repeatability, directly measuring 0–50 sccm flows. For higher flows (>50 sccm), a shunt technique extends the test range based on the 0–10 sccm linear region, where response time is <1 s with error <0.9%. Non-contact operation ensures high stability and long lifespan. The sensor shows outstanding performance and broad application prospects in flow measurement. Full article
►▼ Show Figures

Figure 1

17 pages, 6132 KB  
Article
Nanostructured Scaffold, Combined with Human Dental Pulp Stem Cell Secretome, Induces Vascularization in Medicinal Leech Model
by Gaia Marcolli, Nicolò Baranzini, Ludovica Barone, Federica Rossi, Laura Pulze, Christina Pagiatakis, Roberto Papait, Annalisa Grimaldi and Rosalba Gornati
Micromachines 2025, 16(10), 1150; https://doi.org/10.3390/mi16101150 - 10 Oct 2025
Viewed by 177
Abstract
As life expectancy continues to increase, age-related disorders are becoming more prevalent. Among these, vascular complications resulting from chronic inflammation are particularly concerning, as they impair angiogenesis and hinder tissue repair, both processes that heavily rely on a well-structured extracellular matrix (ECM). In [...] Read more.
As life expectancy continues to increase, age-related disorders are becoming more prevalent. Among these, vascular complications resulting from chronic inflammation are particularly concerning, as they impair angiogenesis and hinder tissue repair, both processes that heavily rely on a well-structured extracellular matrix (ECM). In this context, MicroMatrix® UBM Particulate, a skin substitute composed of collagen, laminin, and proteoglycans, appears to offer properties conducive to tissue regeneration. The aim of this study was to evaluate the regenerative potential of MicroMatrix® combined with the Secretome of human Dental Pulp Stem Cells (hDPSC-S), using the medicinal leech Hirudo verbana, a well-established model for studying wound healing, angiogenesis, and tissue regeneration. Adult leeches were injected with MicroMatrix® either suspended in FBS-free medium (CTRL) or supplemented with hDPSC-S. 1-week post-treatment, the animals were sacrificed and subjected to morphological and immunohistochemical analyses. Our findings revealed that MicroMatrix® successfully integrated into the leech body wall. Notably, when supplemented with hDPSC-S, there was a marked increase in cell infiltration, including telocytes and Hematopoietic Precursor Stem Cells, along with a significantly higher vessel density compared to CTRL. These results support the effectiveness of the cell-free device composed of MicroMatrix® and hDPSC-S, highlighting its potential as a promising strategy for regenerative therapies aimed at treating complex wounds with poor vascularization. Full article
►▼ Show Figures

Figure 1

11 pages, 5294 KB  
Article
A Mini-Two-Path Mach–Zehnder Interferometer Sensor with High Curvature Sensitivity Based on Four-Mode Fiber
by Wuming Wu, Jiayi Qian, Yuechun Shi and Xiaojun Zhu
Micromachines 2025, 16(10), 1149; https://doi.org/10.3390/mi16101149 - 10 Oct 2025
Viewed by 308
Abstract
We have proposed and presented a hybrid mini-two-path Mach–Zehnder interferometer (MTP-MZI) sensor based on four-mode fiber (FMF), where the reference path comprises of a section of a single-mode fiber (SMF), and the sensing path adopts a structure of SMF-FMF-SMF (SFS). Using arc discharge [...] Read more.
We have proposed and presented a hybrid mini-two-path Mach–Zehnder interferometer (MTP-MZI) sensor based on four-mode fiber (FMF), where the reference path comprises of a section of a single-mode fiber (SMF), and the sensing path adopts a structure of SMF-FMF-SMF (SFS). Using arc discharge technology, the two paths are effectively fused and coupled, resulting in a robust MTP-MZI structure sensor. In the curvature detection, the maximum intensity sensitivity of curvature reaches 168.41 dB/m−1 when the curvature ranges change from 0 m−1 to 0.091 m−1. To the best of our knowledge, it is the highest curvature sensitivity in the MZI fiber sensor with intensity modulation. Furthermore, we also conducted a temperature-sensing experiment. The experiment results show that the maximum temperature sensitivity is only 78 pm/°C with a temperature range of 30–65 °C. The diverse exhibition of sensing performance for curvature and temperature enables us to effectively mitigate cross-sensitivity challenges. These results provide the experimental basis for developing a high-sensitivity sensor by employing the mini-two-path structure combined with specialty fibers. Full article
(This article belongs to the Special Issue High-Sensitivity Fiber-Optic Sensors: From Design to Applications)
►▼ Show Figures

Figure 1

19 pages, 1885 KB  
Article
Theoretical Model for a Pneumatic Nozzle–Cylindrical Flapper System
by Peimin Xu, Kazuaki Inaba and Toshiharu Kagawa
Micromachines 2025, 16(10), 1148; https://doi.org/10.3390/mi16101148 - 10 Oct 2025
Viewed by 289
Abstract
To increase semiconductor production yield and meet the growing global demand, air bearings offering higher processing speeds and reduced friction losses have been proposed as an ideal solution. However, due to the non-contact support characteristic of air bearings, challenges such as shaft displacement [...] Read more.
To increase semiconductor production yield and meet the growing global demand, air bearings offering higher processing speeds and reduced friction losses have been proposed as an ideal solution. However, due to the non-contact support characteristic of air bearings, challenges such as shaft displacement caused by processing resistance inevitably arise. As an engineering requirement, the shaft must restrict lateral deflection to within 30 μm under transverse force. In our previous research, a compensation system using a nozzle–flapper mechanism as a displacement sensor was proposed to address shaft displacement. The effectiveness of the nozzle–flapper system in measuring shaft displacement was validated at rotational speeds up to 20,000 rpm. Furthermore, the compensation system’s ability to maintain the shaft’s initial position under a 5 N external force was verified in related collaborative research. In this study, building upon prior work, we further analyze the system characteristics of the cylindrical nozzle–flapper. This includes modeling the geometric space formed by the specific shape of the cylindrical flapper and nozzle and proposing an airflow hypothesis based on this geometry. The hypothesis is incorporated into the theoretical model of a standard nozzle–flapper system, resulting in an optimized theoretical method applicable to cylindrical configurations. Experimental results validating the effectiveness of the proposed model are also presented. Full article
(This article belongs to the Special Issue Flexible and Biodegradable Electronics and Novel Semiconductor Devices)
►▼ Show Figures

Figure 1

12 pages, 1430 KB  
Article
Influence of LPCVD-Si3N4 Thickness on Polarization Coulomb Field Scattering in AlGaN/GaN Metal–Insulator–Semiconductor High-Electron-Mobility Transistors
by Guangyuan Jiang, Weikang Li, Xin Luo, Yang Liu, Chen Fu, Qingying Zhang, Guangyuan Zhang, Zhaojun Lin and Peng Cui
Micromachines 2025, 16(10), 1147; https://doi.org/10.3390/mi16101147 - 10 Oct 2025
Viewed by 314
Abstract
The thickness of the LPCVD-Si3N4 gate dielectric layer significantly influences the electron transport properties of AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs), but the mechanism by which it affects polarization Coulomb field (PCF) scattering remains largely unexplored. In this study, AlGaN/GaN MIS-HEMTs [...] Read more.
The thickness of the LPCVD-Si3N4 gate dielectric layer significantly influences the electron transport properties of AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs), but the mechanism by which it affects polarization Coulomb field (PCF) scattering remains largely unexplored. In this study, AlGaN/GaN MIS-HEMTs with LPCVD-Si3N4 gate dielectric thicknesses of 0 nm, 5 nm, and 20 nm were fabricated, and the influence of LPCVD-Si3N4 thickness on PCF scattering was systematically investigated. Through electrical measurements and theoretical calculations, the relationship between LPCVD-Si3N4 gate dielectric layer thickness, additional polarization charge (∆ρ), two-dimensional electron gas (2DEG) density, and 2DEG mobility was analyzed. The results show that increasing the LPCVD-Si3N4 thickness reduces the vertical electric field in the AlGaN barrier, weakening the inverse piezoelectric effect (IPE) and reducing ∆ρ. Further analysis reveals that the ∆ρ exhibits a non-monotonic dependence on negative gate voltage, initially increasing and subsequently decreasing, due to the competition between strain accumulation and stress relaxation. Meanwhile, the 2DEG mobility limited by PCF (μPCF) decreases monotonically with increasing negative gate voltage, mainly due to the progressive weakening of the 2DEG screening effect. The research results reveal the physical mechanism by which LPCVD-Si3N4 thickness regulates PCF scattering, providing theoretical guidance for optimizing gate dielectric parameters and enhancing the performance of AlGaN/GaN MIS-HEMTs. Full article
(This article belongs to the Section D1: Semiconductor Devices)
►▼ Show Figures

Figure 1

14 pages, 4599 KB  
Article
A Numerical and Experimental Study on the Enrichment Performance of a Novel Multi-Physics Coupling Microchannel
by Qiao Liu, Ruiju Shi and Tongxu Gu
Micromachines 2025, 16(10), 1146; https://doi.org/10.3390/mi16101146 - 10 Oct 2025
Viewed by 257
Abstract
The coupled method of inertial focusing and magnetic separation is effective for detecting and isolating circulating tumor cells (CTCs) from blood, wherein the design of a multi-physics coupled microfluidic device plays a critical role in the sorting efficiency. This paper presents a novel [...] Read more.
The coupled method of inertial focusing and magnetic separation is effective for detecting and isolating circulating tumor cells (CTCs) from blood, wherein the design of a multi-physics coupled microfluidic device plays a critical role in the sorting efficiency. This paper presents a novel compact microfluidic device that combines inertial and magnetic forces for CTC separation. Using the finite element method, the effects of three major parameters (e.g., fluid velocity, particle properties, and magnetic field distribution) on sorting efficiency were comprehensively investigated and discussed. Simulated and experimental results demonstrate that the designed compact microfluidic device with coupled physical fields achieves high separation purity (>98%) for CTCs larger than 19 μm in diameter over a wide range of parameters, such as a fluid velocity greater than 3.5 × 10−8 m3/s, a remanent flux density between 1.08 T and 1.28 T, and the position of the magnet ranging from 2.5 mm to 4 mm. Full article
(This article belongs to the Special Issue Recent Progress of Lab-on-a-Chip Assays)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-101
Previous Issue
Back to TopTop