Journal Description
Micromachines
Micromachines
is a peer-reviewed, open access journal on the science and technology of small structures, devices and systems, published monthly online by MDPI. The Chinese Society of Micro-Nano Technology (CSMNT) and AES Electrophoresis Society are affiliated with Micromachines and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), PubMed, PMC, Ei Compendex, dblp, and other databases.
- Journal Rank: JCR - Q2 (Instruments and Instrumentation) / CiteScore - Q1 (Mechanical Engineering)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 16.6 days after submission; acceptance to publication is undertaken in 2.6 days (median values for papers published in this journal in the first half of 2026).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Testimonials: See what our editors and authors say about Micromachines.
- Companion journal: Micro.
- Journal Cluster of Instruments and Instrumentation: Actuators, AI Sensors, Instruments, Metrology, Micromachines and Sensors.
Impact Factor:
3.5 (2025);
5-Year Impact Factor:
3.5 (2025)
Latest Articles
A Luneburg Lens Antenna for High-Speed Railway Communication
Micromachines 2026, 17(7), 820; https://doi.org/10.3390/mi17070820 (registering DOI) - 7 Jul 2026
Abstract
To address the problems in high-speed railway communication, such as large signal penetration loss through carriages, difficulty in long-distance strip coverage, and limited coverage range of traditional base station antennas, this paper designs a cylindrical Luneburg lens antenna operating at the 1800/FA frequency
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To address the problems in high-speed railway communication, such as large signal penetration loss through carriages, difficulty in long-distance strip coverage, and limited coverage range of traditional base station antennas, this paper designs a cylindrical Luneburg lens antenna operating at the 1800/FA frequency bands. A dual-polarized feed antenna with a dipole structure is designed, loaded with X-shaped metal strips for out-of-band suppression, and integrated with a four-layer dielectric stratified cylindrical Luneburg lens, which uses its graded permittivity distribution to achieve beam focusing, enhance gain, narrow the horizontal beamwidth, and maintain a wide vertical beamwidth. Simulation results show that the lens can stably improve the gain by about 5 dBi; measured results indicate that the antenna has port isolation higher than 35 dB, good impedance matching, and measured gain of 12.4–13.3 dBi within the 1.7–2.1 GHz band, which is highly consistent with the simulation. This antenna can effectively adapt to the long-distance strip coverage scenario along high-speed railways, reduce the base station deployment density, and provide an engineering solution for the optimization of high-speed railway communication coverage.
Full article
(This article belongs to the Special Issue Electromagnetic Metamaterials and Metasurfaces: From Design to Applications)
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Open AccessArticle
Optimized Hough Circle Transform for Automated Microparticle Counting in Microfluidic Platforms
by
Songyuan Yan, Trevor Gerdes, Harbour Li, Timothy Morse and Lawrence Kulinsky
Micromachines 2026, 17(7), 819; https://doi.org/10.3390/mi17070819 - 7 Jul 2026
Abstract
Accurate identification and enumeration of microscopic particles are important for microfluidic analysis, electrokinetic studies, and microscopy-based characterization of microfabricated systems. This study presents an optimized Hough Circle Transform (HCT) workflow for automated particle detection, sizing, and counting. Gold interdigitated electrode arrays (IDEAs) were
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Accurate identification and enumeration of microscopic particles are important for microfluidic analysis, electrokinetic studies, and microscopy-based characterization of microfabricated systems. This study presents an optimized Hough Circle Transform (HCT) workflow for automated particle detection, sizing, and counting. Gold interdigitated electrode arrays (IDEAs) were fabricated on wafer substrates to generate electroosmotic flow, and 3 μm and 5 μm polystyrene microbeads were used as model particles. The final workflow incorporates parallelized multicore parameter optimization and composite statistical metrics based on detection accuracy and frame-to-frame standard deviation, enabling a small manually counted calibration set to be converted into locked detection parameters. In the final validation workflow, 10 manually counted calibration frames were used to optimize HCT parameters for each of four scenarios, and the locked parameters were then validated on 50 new frames per scenario (200 validation frames total) with two independent annotators. Mean validation success rates were 85.1% for 3 μm beads, 90.0% for 5 μm beads, 86.1% for 3 μm beads in mixed suspensions, and 87.2% for 5 μm beads in mixed suspensions, corresponding to object-level error rates of 17.9%, 10.9%, 19.9%, and 13.7%, respectively. Compared with the historical Generation I serial workflow, the optimized workflow reduced parameter-selection time from 24–48 h to 1–2 h, and the runtime image-processing time was approximately 45 ms per frame during offline analysis. These results show that parameter optimization is essential for robust HCT-based particle enumeration and that the workflow provides a practical analytical tool for microfluidic device characterization and electrokinetic experiments.
Full article
(This article belongs to the Special Issue Recent Development of Micro/Nanofluidic Devices, 3rd Edition)
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Open AccessArticle
MOSFET-Oriented Current Sharing Control Strategy for Scalable Parallel DC/DC Converters
by
Mingzhe Qu, Yuan Zhou, Zhigang Zhang, Liangxing Hu and Yu Zhang
Micromachines 2026, 17(7), 818; https://doi.org/10.3390/mi17070818 - 7 Jul 2026
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Parallel DC/DC converter modules provide a feasible approach for achieving power scalability in various power conversion systems. This paper investigates an MOSFET-based lagging leg series diodes phase-shift full-bridge (LLSD-PSFB) converter and proposes a three-loop current-sharing control strategy for coordinated parallel operation. The strategy
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Parallel DC/DC converter modules provide a feasible approach for achieving power scalability in various power conversion systems. This paper investigates an MOSFET-based lagging leg series diodes phase-shift full-bridge (LLSD-PSFB) converter and proposes a three-loop current-sharing control strategy for coordinated parallel operation. The strategy incorporates a voltage loop, a current loop, and a current-sharing loop to mitigate load current imbalance caused by MOSFET parameter mismatches and module inconsistencies. The operating principle and parameter design of the single-module LLSD-PSFB converter are analyzed, and an averaged model is established. Based on this model, a small-signal model of the parallel system is derived to evaluate system stability and current-sharing performance. Simulation results demonstrate that the proposed control scheme effectively improves current-sharing accuracy and dynamic response. An experimental prototype is developed to validate the theoretical and simulation results. The experimental results confirm that the proposed three-loop control strategy achieves high current-sharing precision and stable operation, demonstrating its effectiveness for parallel DC/DC converter systems and its potential for scalable high-power applications.
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Open AccessPerspective
A Thermodynamic Framework for Reliability Kinetics
by
Joseph B. Bernstein
Micromachines 2026, 17(7), 817; https://doi.org/10.3390/mi17070817 - 7 Jul 2026
Abstract
Empirical power-law relationships are widely used in reliability physics to describe degradation kinetics and predict lifetime. Such behavior appears across diverse failure mechanisms, including time-dependent dielectric breakdown (TDDB), hot-carrier injection (HCI), bias temperature instability (BTI), electromigration (EM), and fatigue. In this work, a
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Empirical power-law relationships are widely used in reliability physics to describe degradation kinetics and predict lifetime. Such behavior appears across diverse failure mechanisms, including time-dependent dielectric breakdown (TDDB), hot-carrier injection (HCI), bias temperature instability (BTI), electromigration (EM), and fatigue. In this work, a thermodynamic framework for reliability kinetics is developed from Gibbs free energy and entropy partitioning, leading to a generalized kinetic equation that incorporates thermal activation, stress acceleration, and accumulated degradation. The formulation introduces two parameters: a stress coefficient, , which describes the influence of externally applied stress, and a correlation coefficient, , which describes how accumulated degradation influences subsequent degradation. Negative values of correspond to self-limiting evolution, positive values correspond to self-amplifying evolution, and represents statistically independent accumulation. Representative reliability mechanisms are interpreted within this framework, with TDDB approaching independent evolution, HCI exhibiting weak self-limiting behavior, BTI showing strong self-limiting behavior, and fatigue exhibiting self-amplifying behavior. Electromigration illustrates the complementary role of stress acceleration through . The proposed framework provides a common thermodynamic interpretation of empirical power-law degradation kinetics and introduces degradation correlation as a complementary descriptor for reliability modeling and lifetime prediction.
Full article
(This article belongs to the Special Issue Reliability Metrology, Testing and Failure Analysis of Semiconductor Devices)
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Open AccessEditorial
MEMS Energy Harvesting: Enabling Self-Powered Solutions
by
Yu Jia
Micromachines 2026, 17(7), 816; https://doi.org/10.3390/mi17070816 - 7 Jul 2026
Abstract
Energy harvesting is a broad family of diverse technologies that scavenge various types of ambient energy (such as light, vibration, human motion, thermal, radiofrequency (RF), radioisotope, etc [...]
Full article
(This article belongs to the Section E:Engineering and Technology)
Open AccessArticle
Phototaxis and Motility of Euglena gracilis in Physiological Saline via Stepwise Acclimation for Biohybrid Microrobotics
by
Kaiya Endo, Soshi Morimoto, Hayato Obayashi, Takayuki Shibata, Shunya Okamoto, Tuhin Subhra Santra and Moeto Nagai
Micromachines 2026, 17(7), 815; https://doi.org/10.3390/mi17070815 - 6 Jul 2026
Abstract
Microrobots navigating the human body require biocompatible actuators capable of functioning in physiological fluids. The microalga Euglena gracilis offers precise phototactic control; however, its operational stability in simulated physiological environments remains unproven. Here, we report that a stepwise acclimation process preserves the robotic
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Microrobots navigating the human body require biocompatible actuators capable of functioning in physiological fluids. The microalga Euglena gracilis offers precise phototactic control; however, its operational stability in simulated physiological environments remains unproven. Here, we report that a stepwise acclimation process preserves the robotic functionality of E. gracilis in 100% phosphate-buffered saline (PBS), 100% fetal bovine serum (FBS), and a NaCl solution at a concentration equivalent to PBS (137 mM). We compared direct transfer against a graduated adaptation protocol, evaluating morphology, swimming speed, motility rate, and phototaxis. Direct transfer to each medium caused near-total immobilization, whereas stepwise acclimation retained motility. Acclimated cells exhibited size reduction (miniaturization) while maintaining their characteristic eccentricity. These adapted cells sustained a negative phototactic response among the remaining motile population, supporting optical controllability despite reduced swimming speed. These results indicate that stepwise acclimation allows E. gracilis to retain partial motility and phototactic controllability under simulated physiological saline conditions, and that the observed miniaturization and preserved photo-responsiveness may be useful features for future biohybrid microrobotics.
Full article
(This article belongs to the Special Issue Micro/Nano Sensors and Actuators for Biomedical Applications: Novel Materials, Innovative Designs, and Emerging Functions)
Open AccessArticle
Split-Type Multiband Filter Design Using Ultra-Miniaturized Substrate-Integrated Coaxial Cavities
by
Ming-Chih Chen, Ci-Fang Jheng, Gawn-Wei Su, Chung-I G. Hsu and Min-Hua Ho
Micromachines 2026, 17(7), 814; https://doi.org/10.3390/mi17070814 - 6 Jul 2026
Abstract
The contribution of this paper is to propose the design and experimental validation of split-type dual- and tri-band bandpass filters (BPFs) based on highly miniaturized substrate-integrated coaxial cavities (SICCs). The proposed split-type multiband filter design achieves exceptional circuit-area efficiency within the SIW-related (substrate-integrated
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The contribution of this paper is to propose the design and experimental validation of split-type dual- and tri-band bandpass filters (BPFs) based on highly miniaturized substrate-integrated coaxial cavities (SICCs). The proposed split-type multiband filter design achieves exceptional circuit-area efficiency within the SIW-related (substrate-integrated waveguide) split-type filter category. The size-reduced SICCs are fabricated using two substrates of different thicknesses. The coupling matrix method is employed to synthesize the responses of the example dual- and tri-band filters. The proposed dual-band filter achieves a circuit size of 0.17 λd × 0.17 λd, with insertion losses of 0.78 and 0.89 dB for the two passbands, and isolation between the passbands exceeding 15 dB. For the tri-band filter, the circuit size is 0.27 λd × 0.34 λd, with the insertion losses of 0.96, 2.6, and 1.21 dB across the three passbands, accompanied by similarly effective isolation. Experimental results validate the circuit designs and performance, demonstrating strong agreement between measured and simulated data.
Full article
(This article belongs to the Special Issue Advanced Microwave Devices and RF Chips: Design, Microfabrication, and Applications)
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Open AccessArticle
The Damage Effects on a HgCdTe Detector of a Short-Infrared Pulsed Laser with Different Pulse Widths
by
Qiheng Wei, Xianfeng Wu, Lingyuan Wu, Yongqiang Zhang, Fuli Tan, Bo Fu, Wei Li and Yanglong Li
Micromachines 2026, 17(7), 813; https://doi.org/10.3390/mi17070813 - 6 Jul 2026
Abstract
The high sensitivity of HgCdTe infrared detectors makes them highly vulnerable to laser irradiation, yet the influence of pulse width on damage behavior in the short-wave infrared (SWIR) band remains insufficiently understood. In this study, we experimentally and numerically investigate the damage effects
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The high sensitivity of HgCdTe infrared detectors makes them highly vulnerable to laser irradiation, yet the influence of pulse width on damage behavior in the short-wave infrared (SWIR) band remains insufficiently understood. In this study, we experimentally and numerically investigate the damage effects of SWIR pulsed lasers on HgCdTe focal plane array detectors, focusing on the role of pulse width. Three lasers with pulse widths of 5.5 ns, 0.6 ms and 2 ms are used to irradiate the detector, and the damage thresholds for spot damage, line damage, and complete failure are measured. Damage morphologies are characterized by optical microscopy and scanning electron microscopy. A finite-element thermal model is also established to calculate transient temperature distributions and theoretical damage thresholds. For the 0.6 ms pulse, the measured thresholds for spot damage, line damage, and complete failure are 5.7 J/cm2, 65.4 J/cm2, and 157.3 J/cm2, respectively; for the 2 ms pulse, these increase to 12.1 J/cm2, 149.3 J/cm2, and 405 J/cm2 due to energy dispersion. Microscopic analysis reveals that spot damage arises from melting of HgCdTe and indium bumps, line damage from partial damage to the read-out integrated circuit (ROIC) layer, and complete failure from melt-through of the ROIC layer. The spot damage threshold of the 5.5 ns pulse is 1.2 J/cm2, while neither line damage nor complete failure occurs even with a 352.5 J/cm2 laser pulse, indicating different damage mechanisms due to a thermal confinement effect. The simulation results agree well with the experimental observations. These findings clarify the pulse-width dependence of damage thresholds and provide practical guidance for detector hardening and photoelectric countermeasure design.
Full article
(This article belongs to the Special Issue Photonic and Optoelectronic Devices and Systems, 5th Edition)
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Open AccessArticle
Modeling and Error Compensation for Concentric Grinding of Spherical Surfaces
by
Baozhen Li, Keyan Song, Dongxu Wu, Lin Sun and Yunfei Li
Micromachines 2026, 17(7), 812; https://doi.org/10.3390/mi17070812 - 5 Jul 2026
Abstract
To improve the form accuracy of spherical surfaces generated by cup-wheel grinding, this paper presents a geometric modeling and error compensation method for concentric grinding of spherical surfaces. A cup-shaped arc grinding wheel, hereafter referred to as a cup wheel, is used as
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To improve the form accuracy of spherical surfaces generated by cup-wheel grinding, this paper presents a geometric modeling and error compensation method for concentric grinding of spherical surfaces. A cup-shaped arc grinding wheel, hereafter referred to as a cup wheel, is used as the grinding tool. The relative motion between the cup wheel and the workpiece is formulated so that the contact arc center of the wheel follows a trajectory that is concentric with the target spherical surface. Based on this principle, trajectory models for both convex and concave spherical surfaces are established, and the geometric constraints for cup-wheel dimension selection are analyzed. To compensate for tool-setting errors and wheel-wear-induced deviations, a central-peak-based error compensation model is further developed. Grinding experiments on a convex spherical sample were conducted to verify the proposed trajectory and compensation models. The results show that the form error PV value was reduced from 57.7 μm to 0.3 μm after compensation, demonstrating the effectiveness of the proposed model in improving spherical form accuracy.
Full article
(This article belongs to the Special Issue Advanced Manufacturing Technology and Systems, 4th Edition)
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Open AccessArticle
A Multifunctional Double-Array Petals Flower-Shaped Microfluidic Chip Combining Affinity and Physical Properties in Isolation of CTCs
by
Hongmei Chen, Peng Zhang, Guosheng Peng and Houtong Liu
Micromachines 2026, 17(7), 811; https://doi.org/10.3390/mi17070811 - 3 Jul 2026
Abstract
Circulating tumor cells (CTCs) are tumor cells that break away from the origin tumors and disseminate in the bloodstream and lymphatic circulation systems. CTCs originate from the original tumor with a similar bimolecular source. This makes CTCs play a vital status in cancer
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Circulating tumor cells (CTCs) are tumor cells that break away from the origin tumors and disseminate in the bloodstream and lymphatic circulation systems. CTCs originate from the original tumor with a similar bimolecular source. This makes CTCs play a vital status in cancer prognosis and diagnosis. However, CTC separation is highly challenging due to rarity and heterogeneity. In the present work, we designed a double-array petal flower-shaped microfluidic chip, a multifunctional capturing and isolation chip combining affinity and physical properties. The chip is composed of three arrays of microfluidic barriers organized one after the other. For the first array, six convex structures are set in each narrow channel. The first structure has a total of 12 such channels, which can increase collision frequency between cancer cells and convex structures in the channel. The second capture structure is one composed of an S-shaped array of concave triangle microcolumns and parabolic circular microcolumns. The advantage of this setting is that it can capture CTCs in the blood flowing into the first structure in 12 directions from multiple angles and multiple times, so as to improve capture efficiency. The third capture structure is composed of elliptical microposts and cylinders. The treated blood is captured for the last time. Because of the round or elliptical shape, it can retain the cell viability to a great extent, which is convenient for later pathological analysis of tumor cells. Simulation of velocity influence, pressure effects, streamline tendency, and shear rates is carried out for each structure. Therefore, theoretical validation has been illustrated to achieve high capture rate and purity. These delicate designs and numerical analysis clarify feasibility for further experiments of CTC enumeration, clinical analysis, and evaluation of cancer therapy.
Full article
(This article belongs to the Special Issue Advances in Microfluidic Chips for Chemical and Biomedical Applications, 2nd Edition)
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Open AccessArticle
An Enhanced Electromagnetic Manipulation System with a Large Workspace, High-Gradient Magnetic Actuation, and Efficient Thermal Management
by
Junkai Zhang, Zerui Li, Yukun Zhong, Aaiza Gul and U Kei Cheang
Micromachines 2026, 17(7), 810; https://doi.org/10.3390/mi17070810 - 2 Jul 2026
Abstract
Magnetic actuation is a fundamental enabling technology for micro/nanorobotics and biomedical manipulation. However, the trade-off between magnetic field gradient, usable workspace, and efficient heat dissipation often conflicts and constrains its performance. Here, we present an enhanced electromagnetic manipulation system (EEMS) based on a
[...] Read more.
Magnetic actuation is a fundamental enabling technology for micro/nanorobotics and biomedical manipulation. However, the trade-off between magnetic field gradient, usable workspace, and efficient heat dissipation often conflicts and constrains its performance. Here, we present an enhanced electromagnetic manipulation system (EEMS) based on a compact, high-efficiency magnetic circuit and an optimized six-electromagnet configuration. By integrating high-permeability structural components and employing finite-element-based optimization, the system achieves a spherical workspace of 106 mm in diameter while maintaining strong and spatially controllable magnetic fields. Experimental results demonstrate magnetic flux densities up to 300 mT and a magnetic field gradient up to 9.5 T/m within the workspace, with a central magnetic field gradient of approximately 2 T/m under continuous operation at 3 A. Thermal simulations and measurements confirm safe operation below human body temperature without active cooling. Magnetic manipulation experiments in viscous environments further validate precise motion control and force balancing, highlighting the system’s potential for advanced magnetic manipulation and intelligent microrobotic applications.
Full article
(This article belongs to the Special Issue Micro-/Nano-Electromagnetic and Acoustic Devices)
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Broadband Wind-Driven Hybrid Triboelectric–Electromagnetic Generator for Sufficient Self-Powered Atmospheric Environment Monitoring
by
Shihan Zhang, Yidi Wang and Likun Gong
Micromachines 2026, 17(7), 809; https://doi.org/10.3390/mi17070809 - 2 Jul 2026
Abstract
Self-powered monitoring systems capable of scavenging ambient mechanical energy are a highly desirable solution to eliminate the reliance on batteries and grid power in remote and distributed atmospheric sensing networks. However, the widespread adoption of such systems is severely hindered by the insufficient
[...] Read more.
Self-powered monitoring systems capable of scavenging ambient mechanical energy are a highly desirable solution to eliminate the reliance on batteries and grid power in remote and distributed atmospheric sensing networks. However, the widespread adoption of such systems is severely hindered by the insufficient output power density of current energy harvesters, which struggle to simultaneously drive environmental sensors, data acquisition units, and wireless transmission modules. In this work, we report a highly integrated hybrid power generation system that couples a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG) to efficiently harvest low-frequency mechanical energy from the surroundings. Through systematic structural optimization and synergistic matching of the two transduction mechanisms, the device achieves an outstanding volumetric power density of 129.9 W·m−3, which represents one of the highest values ever reported for hybrid nanogenerators targeting self-powered environmental applications. The output characteristics of both the TENG and EMG units under varying load impedances are thoroughly characterized, revealing the optimal operating points for maximum power extraction. A tailored power management module, consisting of rectification, energy storage, and regulation circuits, is designed to convert the irregular alternating output into a stable direct-current supply. To demonstrate the practical viability of the system, we construct a complete self-powered atmospheric environment monitoring node, which integrates multiple environmental sensors, a data acquisition module, and a wireless transmission module. Driven exclusively by the hybrid TENG–EMG generator under ambient mechanical excitation, the node successfully performs real-time sensing, signal processing, and remote data communication without any external power input. This work not only provides a record-high power density among hybrid generators for environmental monitoring, but also establishes a feasible pathway toward maintenance-free, widely distributed, and truly autonomous atmospheric sensing networks. The presented strategy of maximizing volumetric power density through hybrid design and impedance engineering can be readily extended to other self-powered systems.
Full article
(This article belongs to the Special Issue Micro-Energy Harvesting Technologies and Self-Powered Sensing Systems)
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Open AccessArticle
Quantum Statistical Behaviors of Carriers in Strong Inversion Layers Associated with Mobility and Threshold Voltage in FinFET Transistors
by
Hsin-Chia Yang, Sung-Ching Chi and Han-Ya Yang
Micromachines 2026, 17(7), 808; https://doi.org/10.3390/mi17070808 - 2 Jul 2026
Abstract
Gated transistors in the form of MOSFET, FinFET, or IGBT are capable of controlling and transferring either signals or powers. These capabilities are closely associated with applied biases on Gates, which surpass the respective threshold voltages. Source/Drain bias, VDS, then establishes
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Gated transistors in the form of MOSFET, FinFET, or IGBT are capable of controlling and transferring either signals or powers. These capabilities are closely associated with applied biases on Gates, which surpass the respective threshold voltages. Source/Drain bias, VDS, then establishes the electric field, EDS, driving carriers to flow with a speed which is proportional to EDS with the proportionality, termed mobility, μ. The mobility somewhat addresses the electrical performances of the specific transistor, and is VGS-dependent, where the generated electric field is perpendicular to the interface in between the Gate and the Gate oxide and is directed across the channel. The mobility may be treated as the collective quantum statistical behaviors of carriers, i.e., electrons or fermions. It is worth analyzing the electrical performances by way of quantum statistics. Nevertheless, the threshold voltages are surprisingly negative on FinFETs as the fitting is performed, which means that IDS would flow even without applied voltage on the Gate. IDS-VDS characteristic curves with negative threshold voltage intriguingly perform just like the other ones with positive threshold voltages. Therefore, there might exist some kind of mechanism enhancing strong inversion layers that is responsible for the characteristics. In this paper, characteristic curves of FinFETs may be well fitted by using both modified characteristic formulas and the proposed kink effects. The extracted parameters (kN, Vth, λ) thus provide information on mobility, concentration of p (1/cm3), or even leakage current. Also, the mobility, μ, here is analyzed by using Fermion statistics. Furthermore, trivial solutions for the specific boundary conditions, VGS = 0 V, surrounding the channel are presented, where one of the possibilities proposed is the mass plasma oscillation of electrons, which might be an option for addressing the negative threshold voltage.
Full article
(This article belongs to the Section D1: Semiconductor Devices)
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Open AccessEditorial
Sensing, Imaging, and Computation as One: Rethinking Microfluidic Platform Design
by
Sevketcan Sarikaya and Horacio D. Espinosa
Micromachines 2026, 17(7), 807; https://doi.org/10.3390/mi17070807 - 1 Jul 2026
Abstract
Living systems do not operate in snapshots [...]
Full article
(This article belongs to the Section B:Biology and Biomedicine)
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Open AccessArticle
An Extrinsic Fabry Perot Fiber Optic Current Transformer Based on PZT Coupling
by
Shiguang Bai, Zhongyuan Li, Yanju Li and Qichao Chen
Micromachines 2026, 17(7), 806; https://doi.org/10.3390/mi17070806 - 1 Jul 2026
Abstract
To address the structural complexity, limited detection sensitivity, and environmental susceptibility of the stable operating point in conventional fiber-optic current transformers for low-current detection, this study proposes a fiber-optic current transformer based on the coupling of an extrinsic Fabry–Perot interferometer (EFPI) and a
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To address the structural complexity, limited detection sensitivity, and environmental susceptibility of the stable operating point in conventional fiber-optic current transformers for low-current detection, this study proposes a fiber-optic current transformer based on the coupling of an extrinsic Fabry–Perot interferometer (EFPI) and a lead zirconate titanate piezoelectric ceramic (PZT). In the proposed sensor, a toroidal magnetic core and an induction winding are used as the current pickup unit to convert the measured alternating current into an induced voltage. This induced voltage directly drives the PZT to generate axial displacement, causing periodic variations in the length of the air Fabry–Perot cavity formed between the fiber end face and the coated quartz diaphragm. As a result, the current signal is converted into an optical interference intensity signal. To prevent the static operating point from deviating from the optimal linear region during EFPI intensity demodulation, a DC-component-feedback-based operating point control method is proposed. By adjusting the driving voltage of the fiber Fabry–Perot tunable filter, the center wavelength of the incident narrowband demodulation light can track the optimal operating point of the interference spectrum, thereby improving the stability of the intensity demodulation process. Experimental results show that the fabricated sensor can generate a stable reflected interference spectrum and exhibits a relatively flat frequency response within the range of 0–7 kHz, indicating its potential for power-frequency current detection under the present laboratory conditions. When the measured current is 0.13 mA, the sensor can still produce a distinguishable sinusoidal output signal. When the measured current increases to 75 mA, obvious nonlinear distortion appears in the output signal, indicating that the sensor is approaching the boundary of its linear detection range. Within the linear operating region, the output peak-to-peak value shows good linearity with the measured current. The results indicate that the proposed EFPI-PZT fiber-optic current transformer has the advantages of a relatively simple structure, clear low-current response, and adjustable structural parameters, providing a reference for the miniaturized design and further development of new fiber-optic current sensors.
Full article
(This article belongs to the Special Issue Micro- and Nanosensors: Fabrication, Applications and Performance Enhancements, 4th Edition)
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Open AccessArticle
A Novel Continuous-Flow PCR Microdevice Operated by a Single Heat Source
by
Weining Song, Di Wu, Yutong Xing and Wenming Wu
Micromachines 2026, 17(7), 805; https://doi.org/10.3390/mi17070805 - 30 Jun 2026
Abstract
This paper presents a constant-temperature, single-heat-source continuous-flow PCR (CF-PCR) microdevice that achieves stable thermal control for denaturation, annealing, and extension on a single platform. Key innovations include: (1) a metal-powder/PDMS thermal conduction block with trapezoidal geometry that generates a programmable temperature gradient and
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This paper presents a constant-temperature, single-heat-source continuous-flow PCR (CF-PCR) microdevice that achieves stable thermal control for denaturation, annealing, and extension on a single platform. Key innovations include: (1) a metal-powder/PDMS thermal conduction block with trapezoidal geometry that generates a programmable temperature gradient and tunable residence times under one heat source; and (2) a thermoelectric cooler (TEC)-based Peltier system that creates distinct high- and low-temperature zones by co-optimizing the hot/cold side temperature difference, spacer material (92% alumina), and input voltage (3.6 V). A self-pressurized gas-diffusion micropump, enabled by a capillary quartz tube at the outlet, drives continuous sample flow without external actuation. The platform features three configurations: an on-chip zoned-heating design, an off-chip coiled-tube setup, and a battery-powered handheld system (727 g, 6 W, ~4 h runtime). Using CNC-machined and thermally bonded PMMA microchips with BSA passivation, the on-chip device achieves ~80% amplification efficiency relative to commercial instruments for H7N9 and pGEM-3Zf(+); the off-chip version reaches ~75%. The portable system yields HPV and RUBV amplification intensities comparable to benchtop devices. This approach provides a practical, scalable solution for “sample-in–answer-out” nucleic acid testing in point-of-care settings.
Full article
(This article belongs to the Topic Micro-Mechatronic Engineering, 2nd Edition)
Open AccessArticle
Process and Mechanism of Cutting Polyamide Films with an Ultraviolet Picosecond Laser
by
Qin Xie, Tian Wang, Yan Zhou, Zeyue Gao, Jie Jiang, Congyi Wu, Bing Wei and Yu Huang
Micromachines 2026, 17(7), 804; https://doi.org/10.3390/mi17070804 - 30 Jun 2026
Abstract
Polyamide (PA) films have been widely utilized in high-precision medical devices and aerospace components, while laser precision cutting technology has significantly broadened their application scope. Although ultraviolet (UV) picosecond lasers are effective for high-precision cutting of PA films, their cutting mechanism and the
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Polyamide (PA) films have been widely utilized in high-precision medical devices and aerospace components, while laser precision cutting technology has significantly broadened their application scope. Although ultraviolet (UV) picosecond lasers are effective for high-precision cutting of PA films, their cutting mechanism and the optimization method for the process remain to be elucidated. First, the mechanism of UV picosecond laser cutting of PA films was investigated through a simulation of the thermal degradation process and analysis of the solid/gas byproduct composition. The results indicate that the photochemical reaction primarily dominates the process, with the photothermal effect contributing synergistically. Second, a cutting quality evaluation framework was established, with the kerf width and heat-affected zone (HAZ) width as its primary metrics, followed by an orthogonal experiment. The experimental results revealed the influence of process parameters on the cutting quality, and it was determined that an optimal process parameter combination exists, identified as 80 mm/s, 1.67 W, and three times (cutting speed, laser power, repetition number of cutting). Under this optimal configuration, narrow kerf (23.6 ± 2.7 μm) and HAZ (28.4 ± 3.3 μm) were achieved.
Full article
(This article belongs to the Special Issue Laser Precision Processing and Intelligent Inspection Technologies for Transparent and Selectively Transmissive Materials)
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Open AccessArticle
Gray Wolf Optimization-Long Short-Term Memory Based Temperature Estimation and Closed-Loop Control Method in Microfluidic Chemiluminescence Immunoassay
by
Xu Xu, Zhongyi Xu, Chuan Lyu, Bo Liang, Congcong Zhou, Xuesong Ye and Jing Wang
Micromachines 2026, 17(7), 803; https://doi.org/10.3390/mi17070803 - 30 Jun 2026
Abstract
Driven by the rising demand for point-of-care testing (POCT) in aging societies, accurate temperature regulation of reaction solutions has become a core technical bottleneck for miniaturized chemiluminescence immunoassay systems, since conventional indirect control strategies inevitably produce systematic deviations. To tackle this challenge, we
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Driven by the rising demand for point-of-care testing (POCT) in aging societies, accurate temperature regulation of reaction solutions has become a core technical bottleneck for miniaturized chemiluminescence immunoassay systems, since conventional indirect control strategies inevitably produce systematic deviations. To tackle this challenge, we present an integrated solution that couples multiphysics simulation, data-driven temperature estimation modeling, and embedded hardware design. We constructed a COMSOL heat transfer model to analyze the thermal performance of the microfluidic chip. Meanwhile, a grey wolf optimization (GWO) enhanced long short-term memory (LSTM) network was developed to infer the unmeasured actual reaction solution temperature based on accessible parameters, including heating voltage, ambient temperature and substrate temperature. The obtained temperature estimation was then fed back to a fuzzy PID controller for closed-loop regulation. Experimental results demonstrated that the GWO-LSTM model limited the estimation error within 0.3 °C, and the steady-state temperature control accuracy reached ±0.2 °C or higher under fluctuating ambient conditions and diverse initial states. For cardiac troponin I (cTnI) detection, the proposed system shortened the incubation duration and reduced the coefficient of variation from 10.77% to 2.69%. This work addresses the key bottleneck restricting precise temperature control in microfluidic chemiluminescence analyzers, which provides robust technical support for the development of next-generation high-performance POCT instruments.
Full article
(This article belongs to the Special Issue Recent Progress of Lab-on-a-Chip Assays)
Open AccessArticle
A Super Memory Processing Unit Based on 3D Stacking and Hybrid Bonding for High-Efficiency AI Computing
by
Ruiyong Zhao, Yibo Hu and Jing Chen
Micromachines 2026, 17(7), 802; https://doi.org/10.3390/mi17070802 - 30 Jun 2026
Abstract
DRAM-based in-memory computing integrates computational regions into the main memory, enabling local data processing within the memory, thereby achieving faster and more efficient data computation. However, enhancing system performance requires addressing a critical challenge: achieving more general and sufficiently powerful data processing capabilities
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DRAM-based in-memory computing integrates computational regions into the main memory, enabling local data processing within the memory, thereby achieving faster and more efficient data computation. However, enhancing system performance requires addressing a critical challenge: achieving more general and sufficiently powerful data processing capabilities within DRAM-PIM. Existing DRAM-PIM implementations often suffer from limited computational capabilities due to the shared standard DRAM package area between memory cells and computational circuits or because the operator circuits are overly customized, which limits their ability to meet required data processing demands. To address this issue, in this paper, we propose a Super Memory Processing Unit (SMPU). The SMPU uses Hybrid Bonding technology to 3D-stack DRAM and many-core computational clusters, enabling large-bandwidth (0.25 TB/s per-bank, 2 TB/s for 8-bank system bandwidth) on-chip data transmission between DRAM and the computational cluster via copper interconnects, effectively breaking the memory wall bottleneck of existing computing architectures. The SMPU constructs a dual-channel fine-grained computational cluster at the logical computing layer, providing flexible and ample computility for various AI models, such as ResNet50 and Llama2. The SMPU uses standard DDR protocols and integrates a new memory space allocation and parsing controller to ensure system compatibility without modifying the host-end hardware, facilitating the integration and invocation of computility in memory particles. Additionally, the SMPU features an independent dual-channel memory-management mechanism within the memory particles, enabling simultaneous multi-channel, multi-modal AI model inference. We compared a CPU system equipped with an SMPU to current computing systems using FPGA simulations. The FPGA simulation results show that, under the same computational configuration, the system with the SMPU improves the performance of ResNet50-v1.5 by up to 5.1× and Llama by up to 27.43× compared to the base system, while reducing system power consumption by 71.6% (ResNet50-v1.5) to 77.8% (Llama 7B).
Full article
(This article belongs to the Special Issue Neuromorphic Memory and Computing-in-Memory Architectures: From Devices to Systems)
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Open AccessArticle
Low-Temperature Direct PECVD Synthesis of Graphene on Si(100) with Increased Methane Flow: Structure and Photoelectric Properties
by
Vidmantas Kumža, Rimantas Gudaitis, Asta Guobienė, Andrius Vasiliauskas and Šarūnas Meškinis
Micromachines 2026, 17(7), 801; https://doi.org/10.3390/mi17070801 - 30 Jun 2026
Abstract
Graphene was directly synthesized on monocrystalline Si(100) at 500 °C by microwave plasma-enhanced chemical vapor deposition using an increased CH4/H2 gas flow ratio. Raman analysis revealed spectral features and intensity ratios consistent with the growth of hydrogenated graphene and revealed
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Graphene was directly synthesized on monocrystalline Si(100) at 500 °C by microwave plasma-enhanced chemical vapor deposition using an increased CH4/H2 gas flow ratio. Raman analysis revealed spectral features and intensity ratios consistent with the growth of hydrogenated graphene and revealed changes in defect structure, graphene layer number, and self-doping. Atomic force microscopy measurements showed that the surface morphology and local conductivity strongly depended on the growth conditions. The electrical and photoelectrical characteristics of graphene/Si junctions were correlated with the Raman parameters and surface morphology. For the hydrogenated graphene samples synthesized at 500 °C, the photocurrent, short-circuit current, and open-circuit voltage were found to be competitive with those of pristine graphene reference samples grown at 700 °C. The results demonstrate the potential of low-temperature direct PECVD synthesis for graphene/Si optoelectronic devices.
Full article
(This article belongs to the Special Issue Low-Dimensional Nano-Scaled Materials: From Principles to Device Application)
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