Search Results (243)

Extreme ultraviolet (EUV) pellicles must withstand intense thermal stress during exposure due to their limited heat dissipation, which results from their ultrathin geometry and the vacuum environment within EUV scanners. To address this challenge, we investigated the crystalline phase-dependent emissivity of nanometer-thick molybdenum disilicide (MoSi₂) membranes. Membranes exhibiting amorphous, hexagonal, and tetragonal phases were independently prepared via controlled annealing, and their thermal radiation properties were evaluated using heat-load testing under emulated EUV scanner conditions. The Hall effect measurements revealed distinct variations in carrier density and mobility across phases, which were theoretically correlated with emissivity using the Lorentz–Drude model. The results demonstrate that emissivity increases in the hexagonal phase due to increased carrier density and reduced scattering, offering improved thermal radiation performance. These findings establish the phase engineering of conductive silicides as a viable strategy for enhancing radiative cooling in EUV pellicles and offer a theoretical framework applicable to other high-temperature nanomaterials. Full article

Mechanical alloying (MA) has been proven to be an energy-efficient synthetic route for the development of high-performance thermoelectric (TE) materials. Higher Manganese Silicide (HMS) phases of the general formula Mn(Si_1−xAl_x)_1.75 (0 ≤ x ≤ 0.05) were prepared by MA implementing a short-time ball-milling process. Powder XRD and SEM analysis were carried out to validate the HMS phases, while small amounts of the secondary phase, MnSi, were also identified, especially for the Al-doped products. Electrical transport properties measurements showed that Al substitution causes an effective hole doping. A remarkable increase in electrical conductivity is observed for the Al-doped phases, while the corresponding reduction in the Seebeck coefficient is indicative of the increase in carrier density. Despite the small percentages of MnSi detected in Al-doped phases, an improvement in TE efficiency is achieved in the series Mn(Si_1−xAl_x)_1.75 (0 ≤ x ≤ 0.05). The 2.5% Al-doped phase exhibits a maximum figure-of-merit (ZT) of 0.43 at 773 K. Moreover, in an effort to utilize recycled silicon byproducts from photovoltaic (PV) manufacturing, Al-doped phases are developed by MA using two types of Si kerf. The two kerf-based products exhibit lower TE efficiencies, due to the increased amounts of the metallic MnSi phase. Full article

ZrB₂-HfB₂ composites allow us to obtain materials characterized by the high chemical resistance characteristic of HfB₂ while reducing density and improving sinterability due to the presence of ZrB₂. Since boride composites are difficult-to-sinter materials. One way to achieve high density during sintering is to add phases that activate mass transport processes and, after sintering, remain as composite components that do not degrade and even improve some properties of the borides. The following paper is a comprehensive review of the effects of various and the most commonly used sintering aids, i.e., SiC, B₄C, WC, MoSi₂, and CrSi₂, on the thermo-chemical properties of the ZrB₂-HfB₂ composites. High-density composites with a complex phase composition dominated by (Zr,Hf)B₂ solid solutions were obtained using a hot pressing method. The tests showed differences in the properties of the composites due to the type of sintering additives used. From the point of view of the thermo-chemical properties, the best additive was silicon carbide. The composites containing SiC, when compared to the initial, pure borides, were characterized by high thermal conductivity λ (80–150 W/m·K at 20–1000 °C), a significantly reduced thermal expansion coefficient (CTE ~6.20 × 10⁻⁶ 1/K at 20–1000 °C), and considerably improved oxidation resistance (up to 1400 °C). Full article

In this study, we propose a bidirectional chemical sensor platform based on a reconfigurable ion-sensitive field-effect transistor (R-ISFET) architecture. The device incorporates Ni-silicide Schottky barrier source/drain (S/D) contacts, enabling ambipolar conduction and bidirectional turn-on behavior for both p-type and n-type configurations. Channel polarity is dynamically controlled via the program gate (PG), while the control gate (CG) suppresses leakage current, enhancing operational stability and energy efficiency. A dual-control-gate (DCG) structure enhances capacitive coupling, enabling sensitivity beyond the Nernst limit without external amplification. The extended-gate (EG) architecture physically separates the transistor and sensing regions, improving durability and long-term reliability. Electrical characteristics were evaluated through transfer and output curves, and carrier transport mechanisms were analyzed using band diagrams. Sensor performance—including sensitivity, hysteresis, and drift—was assessed under various pH conditions and external noise up to 5 V_pp (i.e., peak-to-peak voltage). The n-type configuration exhibited high mobility and fast response, while the p-type configuration demonstrated excellent noise immunity and low drift. Both modes showed consistent sensitivity trends, confirming the feasibility of complementary sensing. These results indicate that the proposed R-ISFET sensor enables selective mode switching for high sensitivity and robust operation, offering strong potential for next-generation biosensing and chemical detection. Full article

This paper presents a novel approach employing localized annealing through Joule heating to enhance the performance of Thin-Film Piezoelectric-on-Silicon (TPoS) MEMS resonators that are crucial for applications in sensing, energy harvesting, frequency filtering, and timing control. Despite recent advancements, piezoelectric MEMS resonators still suffer from anchor-related energy losses and limited quality factors (Qs), posing significant challenges for high-performance applications. This study investigates interface modification to boost the quality factor (Q) and reduce the motional resistance, thus improving the electromechanical coupling coefficient and reducing insertion loss. To balance the trade-off between device miniaturization and performance, this work uniquely applies DC current-induced localized annealing to TPoS MEMS resonators, facilitating metal diffusion at the interface. This process results in the formation of platinum silicide, modifying the resonator’s stiffness and density, consequently enhancing the acoustic velocity and mitigating the side-supporting anchor-related energy dissipations. Experimental results demonstrate a Q-factor enhancement of over 300% (from 916 to 3632) and a reduction in insertion loss by more than 14 dB, underscoring the efficacy of this method for reducing anchor-related dissipations due to the highest annealing temperature at the anchors. The findings not only confirm the feasibility of Joule heating for interface modifications in MEMS resonators but also set a foundation for advancements of this post-fabrication thermal treatment technology. Full article

To enhance the mechanical properties of NbMoTaW refractory high-entropy alloys (RHEAs), Si was added at varying concentrations (x = 0, 0.25, and 0.5) via vacuum induction levitation melting (re-melted six times for homogeneity). The microstructure and mechanical properties of NbMoTaWSi_x (x = 0, 0.25, and 0.5) RHEAs were characterized using scanning electron microscopy (SEM), universal testing, microhardness testing, and tribological equipment. Experimental results manifested that Si addition induces the formation of the (Nb,Ta)₅Si₃ phase, and the volume fraction of the silicide phase increases with higher Si content, which significantly improves the alloy’s strength and hardness but deteriorates its plasticity. Enhanced wear resistance with Si addition is attributed to improved hardness and oxidation resistance. Tribological tests confirm that Si₃N₄ counterfaces are optimal for evaluating RHEA wear mechanisms. This work can provide guidance for the fabrication of RHEAs with excellent performance. Full article

This article discusses the development of a technology for producing nickel- and chromium-containing ferroalloy through the carbothermic reduction of low-grade ores from the Batamsha deposit. Thermodynamic modeling of phase formation was carried out using the Chemistry 10 software package, along with a series of pilot-scale smelting experiments in a submerged arc furnace. The influence of technological parameters, particularly slag basicity, on the distribution of nickel and chromium in the alloy was studied. The results of an X-ray phase analysis confirmed the modeling conclusions, revealing the presence of nickel and chromium silicide phases. The proposed technology demonstrated a high metal recovery rate and process stability, indicating its potential for industrial application in Kazakhstan. Full article

Thermal spraying technique has potential in manufacturing economic, profitable thermoelectric coatings. In order to characterize the electrical performance of thermoelectric coatings more conveniently, a simple setup for thermoelectric power factor of thermoelectric coatings is designed and developed. The indigenously designed setup is simple and low-cost. The compact structure makes it easy to cooperate with existing heating furnace, allowing a fast measurement in a variable temperature range. The differential method and the off-axis four-point geometry are used in Seebeck coefficient and electrical resistivity measurement, respectively. The Spring-load unit and other details of construction of the setup are described specifically. The Seebeck coefficient of the plasma-sprayed higher manganese silicide (HMS) coating was measured to be approximately 132.35 μV/K at 150 °C, with measurements showing high linearity (R² > 0.99). The setup demonstrated reliable electrical resistivity results for Cr20Ni80 alloy, closely matching published values (1.16 × 10⁻⁶ Ω·m vs. 1.10 × 10⁻⁶ Ω·m). HMS coating was also characterized from 50 °C to 500 °C to validate the setup on thermoelectric performance characterization across a wide temperature range. These results confirm the reliability of the developed setup. Full article

Refractory metal-based Mo-Si-B alloys have long been considered the most promising candidates for replacing nickel-based superalloys in the aerospace and energy sector due to their outstanding mechanical properties and good oxidation of the Mo-silicide phases. In general, the addition of vanadium to Mo-Si-B alloys leads to a significant density reduction, while small amounts of titanium provide additional strengthening without changing the phase evolution within the Mo_ss-Mo₃Si-Mo₅SiB₂ phase field. In this work, high-energy ball milling studies on Mo-40V-9Si-8B, substituting both molybdenum and vanadium with 2 and 5 at. % Ti in all constituents, were performed to evaluate the potential milling parameters and investigate the effects of Ti doping on the milling characteristics and phase formation of these multicomponent alloys. After different milling durations, the powders were analysed with regard to their microstructure, particle size, oxygen concentration and microhardness. After heat treatment, the silicide phases (Mo,V)₃Si and (Mo,V)₅SiB₂ precipitated homogeneously within a (Mo,V) solid solution matrix phase. Thermodynamic phase calculations using the CALPHAD method showed good agreement with the experimental phase compositions after annealing, confirming the stability of the observed microstructure. Full article

Si-based photonics has garnered considerable attention as a future device for complementary metal–oxide–semiconductor (CMOS) computing. However, few studies have investigated Si-based light sources highly compatible with Si ultra large-scale integration processing. In this study, we observed stable light emission at room temperature from superatom-like β–FeSi₂–core/Si–shell quantum dots (QDs). The β–FeSi₂–core/Si–shell QDs, with an areal density as high as ~10¹¹ cm⁻² were fabricated by self-aligned silicide process of Fe–silicide capped Si–QDs on ~3.0 nm SiO₂/n–Si (100) substrates, followed by SiH₄ exposure at 400 °C. From the room temperature photoluminescence characteristics, β–FeSi₂ core/Si–shell QDs can be regarded as active elements in optical applications because they offer the advantages of photonic signal processing capabilities and can be combined with electronic logic control and data storage. Full article

CoCrFeNiSi_x (where x = 0, 0.5, 1.0, 1.5, 2.0 mol, named as H4, Si_0.5, Si_1.0, Si_1.5, and Si_2.0, respectively) high-entropy alloys (HEAs) were fabricated via hot-press sintering. The effects of Si content on the phase structure, microstructure, and mechanical properties of HEAs were investigated. The results show that the H4 alloy consists of a single FCC phase. As the Si content increases, the phases of CoCrFeNiSi_x HEAs transform from the FCC phase to the BCC and silicide phases. An increase in Si content can significantly enhance the hardness and yield strength of the alloys, yet at the expense of their plasticity. When the Si content increases from 0 to 2.0 mol, the hardness of the alloy increases from 280 HV to 1060 HV, the yield strength rises from 760 MPa to 1640 MPa, and the fracture strain drops to 6%. The strengthening mechanism of this HEA system mainly stems from the synergistic effect of solid solution strengthening and precipitation strengthening of silicide phases. Full article

Additive manufacturing (AM) technologies allow for the creation of components with greater design flexibility. The complexity in geometry and composition can enhance functionality, while parts made from multiple materials have the capacity to deliver improved performance. Nonetheless, most multimaterial printing methods are still in their infancy and face numerous challenges. Numerous materials require individual post-treatment, and some may not be compatible with each other regarding shrinkage, melting or sintering temperatures, and interactions. In this study, we introduce a technique for producing a metal–ceramic multimaterial prototype for electronic packages through powder-bed additive manufacturing technology. Silicon carbide-based ceramic substrate was manufactured by selective laser melting, on which molybdenum-based conductive tracks were printed. The results indicated that the SiC-based samples exhibit a relatively uniform microstructure with homogeneously distributed porosity. Mo-based powder containing 5% silicon was successfully SLM-ed on the SiC layer. The microstructural and chemical analyses show that Mo reacted with Si during selective laser melting, resulting in formation of molybdenum silicides. The surface of Mo-based layer surface is smooth; however, there are few cracks on it. The Vickers hardness was measured to be 7.6 ± 1 GPa. The electrical resistivity of the conductive track is 2.8 × 10⁻⁵ Ω·m. Full article

TiSi₂ and Ti₅Si₃ were synthesized through a simple and cost-effective process, providing a sustainable way to recycle titanium oxide and silicon wastes from industry. The reaction process was investigated at 1500 °C under various slag/silicon ratios and slag compositions. TiSi₂ was synthesized successfully under all experimental conditions, with nearly complete extraction of titanium oxide from the slag within 5 h under optimized conditions. TiSi₂ initially formed at the slag/silicon interface, followed by the formation of Ti₅Si₃ as TiSi₂ droplets fell through the slag. The production rate of TiSi₂ was higher than that of Ti₅Si₃. Kinetic analysis showed that the reaction rate constant ranged from 1.2 × 10⁻⁵ to 4.3 × 10⁻⁴ s⁻¹. Viscosity and basicity were not the limiting factors of the kinetics in this work. The amount of TiO₂ in the slag significantly influenced the reaction process, with slag containing less than 30 mol% TiO₂ identified as optimal for efficient titanium extraction and a high synthesis rate. Full article

High-entropy silicide (MeSi₂) coating was prepared by the slurry method and silicon infiltration method using Mo, Cr, Ta, Nb, W, and Si elemental powders as raw materials. The coating consisted of four layers, including a porous MeSi₂ layer, a (CrTa)Si layer, a TaSi₂ layer, and a Ta₅Si₃ layer from outside to inside. At 600 °C, Si was preferentially oxidized to form SiO₂ oxide film. The mass gain rate of the coating was 0.2 mg/cm² over a period of 100 h oxidation, eliminating the phenomenon of low-temperature pulverization. At 1200 °C, MeSi₂ coating had a protection time of 20 h. During the oxidation process, the coating generated metal oxides, forming a thin SiO₂ oxide film. TaSi₂ and Ta₅Si₃ gradually transformed into Ta₂O₅, and the coating eventually failed. Full article

Lithography is crucial to semiconductor manufacturing, enabling the production of smaller, more powerful electronic devices. This review explores the evolution, principles, and advancements of key lithography techniques, including extreme ultraviolet (EUV) lithography, electron beam lithography (EBL), X-ray lithography (XRL), ion beam lithography (IBL), and nanoimprint lithography (NIL). Each method is analyzed based on its working principles, resolution, resist materials, and applications. EUV lithography, with sub-10 nm resolution, is vital for extending Moore’s Law, leveraging high-NA optics and chemically amplified resists. EBL and IBL enable high-precision maskless patterning for prototyping but suffer from low throughput. XRL, using synchrotron radiation, achieves deep, high-resolution features, while NIL provides a cost-effective, high-throughput method for replicating nanostructures. Alignment marks play a key role in precise layer-to-layer registration, with innovations enhancing accuracy in advanced systems. The mask fabrication process is also examined, highlighting materials like molybdenum silicide for EUV and defect mitigation strategies such as automated inspection and repair. Despite challenges in resolution, defect control, and material innovation, lithography remains indispensable in semiconductor scaling, supporting applications in integrated circuits, photonics, and MEMS/NEMS devices. Various molecular strategies, mechanisms, and molecular dynamic simulations to overcome the fundamental lithographic limits are also highlighted in detail. This review offers insights into lithography’s present and future, aiding researchers in nanoscale manufacturing advancements. Full article