Third-generation Semiconductor Research Articles

Exploring Defect Dynamics and Twin-Layer Interactions in SiC Crystals through Molecular Simulations.

Silicon carbide (SiC), a third-generation semiconductor material, is pivotal for applications in new energy vehicles, aerospace, and high-speed electronics, owing to its superior properties. This study delves into the twin-induced growth behaviors of SiC crystals through molecular dynamics simulations at temperatures ranging from 2700 to 3200 K. It focuses on the wurtzite and zinc blende SiC structures, revealing dynamic defect behavior during growth, including an initial rise and subsequent decrease in vacancies, with particular emphasis on prevalent defects within zinc blende twin layers. A significant finding is the direct correlation between temperature and growth rates across different SiC structures, highlighting temperature control as essential for optimizing crystal quality. Furthermore, this work contributes to the analysis of the interactions of twin layers and their impact on structural stability and defect formation in SiC crystals. The insights gained here have substantial implications for the semiconductor industry, potentially enhancing device performance by better controlling growth conditions and defect management in SiC-based electronic and optoelectronic devices.

Densification, microstructure, thermal and mechanical properties of Si3N4 ceramics: Effect of Y2Si4N6C and MgSiN2 content

The rapid development of third-generation semiconductors urgently requires ceramic substrates with excellent performance. In this work, silicon nitride (Si3N4) ceramics were successfully prepared via gas-pressure sintering (GPS) using Y2Si4N6C and MgSiN2 as additives. The influence of Y2Si4N6C–MgSiN2 content on the liquid phase properties and microstructure of Si3N4 ceramics was clarified. The use of Y2Si4N6C–MgSiN2 not only did not introduce additional oxygen but also consumed SiO2 and purified the β-Si3N4 lattice. The increase in N/O formed a nitrogen-rich liquid phase, which led to the microstructure of Si3N4 ceramics having a bimodal distribution. The relationship between different degrees of bimodal microstructure and properties was explored. When the Y2Si4N6C–MgSiN2 content was 9 wt%, Si3N4 ceramics obtained excellent thermal and mechanical properties due to lattice purification, Si3N4/Si3N4 continuity increase, the largest average grain diameter, and a bimodal distribution microstructure with moderate grain size distribution. The thermal conductivity was 116.7 W m−1 K−1, the fracture toughness was 10.7 ± 0.35 MPa m1/2, and the bending strength was 767 ± 29.6 MPa.

The role of Cr in optimizing properties of Fe–B–C–P–Si–Mo–Cr metallic glasses for applications

With the rapid development of third-generation semiconductors, there is an urgent need to develop high-performance soft magnetic Fe-based metallic glasses tailored particularly for their high-frequency applications. In this work, new Fe76−yB7C7P7Si3Moy−xCrx (y = 0, 1, 2, 3 at.%, x ≤ y) alloys with relatively high glass-forming ability (GFA) were developed. The effects of replacing Mo with Cr on GFA, thermodynamic properties, soft magnetic properties, electrical resistivity (ρ), and corrosion resistance at different Fe contents were systematically studied. The possible causes of GFA variation were discussed. The results show that the addition of a small amount of Cr replacing Mo under different Fe contents would not lead to a decrease in GFA. The critical sizes of Cr-containing glassy alloys are 1–2.5 mm. These alloys possess relatively high saturation magnetization (Ms) of 1.29–1.41 T and lower coercivity (Hc) of 0.7–1.8 A/m, contributing to the reduction of hysteresis loss. In addition, Cr increases ρ of the alloys, reaching up to 162 μΩ cm, which is beneficial to reducing eddy current loss at high frequency. Furthermore, Cr effectively enhances corrosion resistance, thereby increasing the service life of the alloys in harsh environments. The role of Cr in these aspects makes it a beneficial element in soft magnetic metallic glasses for high-frequency applications.

Bismuth as a buffer layer for metal contact with silicon carbide studied by In situ photoelectron spectroscopy

Silicon carbide (SiC) is a promising third-generation semiconductor due to its wide bandgap. However, the high Schottky barrier and metal-induced gap states (MIGS) at the metal/SiC interface present significant challenges for device fabrication, leading to high contact resistance and poor current delivery. This study proposes the use of bismuth (Bi), with its semimetallic properties and gap-state saturation effect, as a contact buffer layer to address these issues. We conducted a systematic investigation of the chemical and electronic characteristics of the Pt/Bi/4H-SiC(0001) system, fabricated via molecular beam epitaxy (MBE), using in situ X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Our findings reveal weak bonding between the Bi buffer layer and the 4H-SiC(0001) surface, resulting in a slight downward band bending effect and the formation of a substantial dipole across the Bi/4H-SiC(0001) interface. Moreover, UPS spectra indicate a reduction in the work function of Pt/Bi/4H-SiC(0001), suggesting the potential for achieving low contact resistance. Notably, the Pt/Bi/4H-SiC(0001) system remains stable when exposed to 1.6×109 Langmuir of oxygen at room temperature, while a bare Bi buffer layer undergoes partial oxidation. These results provide a comprehensive understanding of the Pt/Bi/4H-SiC(0001) interfaces and strategies for improving metal/SiC contacts.

Investigating the Corrosion Resistance of Different SiC Crystal Types: From Energy Sectors to Advanced Applications.

Silicon carbide, as a third-generation semiconductor material, plays a pivotal role in various advanced technological applications. Its exceptional stability under extreme conditions has garnered a significant amount of attention. These superior characteristics make silicon carbide an ideal candidate material for high-frequency, high-power electronic devices and applications in harsh environments. In particular, corrosion resistance in natural or artificially acidic and alkaline environments limits the practical application of many other materials. In fields such as chemical engineering, energy conversion, and environmental engineering, materials often face severe chemical erosion, necessitating materials with excellent chemical stability as foundational materials, carriers, or reaction media. Silicon carbide exhibits outstanding performance under these conditions, demonstrating significant resistance to corrosive substances such as hydrochloric acid, sulfuric acid, nitric acid, and alkaline substances such as potassium hydroxide and sodium hydroxide. Despite the well-known chemical stability of silicon carbide, the stability conditions of its different types (such as 3C-, 4H-, and 6H-SiC polycrystals) in acidic and alkaline environments, as well as the specific corrosion mechanisms and differences, warrant further investigation. This Review not only delves deeply into the detailed studies related to this topic but also highlights the current applications of different silicon carbide polycrystals in chemical reaction systems, energy conversion equipment, and recycling processes. Through a comprehensive analysis, this Review aims to bridge research gaps, offering a comparative analysis of the advantages and disadvantages between different polymorphs. It provides material scientists, engineers, and developers with a thorough understanding of silicon carbide's behavior in various chemical environments. This work will propel the research and development of silicon carbide materials under extreme conditions, especially in areas where chemical stability is crucial for device performance and durability. It lays a solid foundation for ultra-high-power, high-integration, high-reliability module architectures, supercomputing chips, and highly safe long-life batteries.

Enhanced contact performance of high-brightness micro-LEDs via ITO/Al anode stack and annealing process

Micro-light-emitting diodes (Micro-LEDs) are a new type of display device based on the third-generation semiconductor gallium nitride (GaN) material which stands out for its high luminous efficiency, elevated brightness, short response times, and high reliability. The contact between anode layers and P-GaN is one of the keys to improving the performance of the devices. This study investigates the impact of electrode structure design and optimized annealing conditions on the anode contact performance of devices. The Micro-LED device with the size of 9.1 μm whose electrode structure is ITO/Ti/Al/Ni/Cr/Pt/Au (100/50/350/100/500/500/5000 Å) exhibits a significant improvement in contact performance after annealing under the Ar gas atmosphere at 500 °C for 5 min. The optimized device exhibited a current of 10.9 mA and a brightness of 298,628 cd/m2 under 5 V. The EQE peak value of Device A is 10.06% at 400 mA.

Synchrotron radiation x-ray topography applied to nitride semiconductor crystals

Gallium nitride (GaN) and aluminum nitride (AlN), as examples of third-generation semiconductors, have attracted significant interest due to their remarkable physical attributes, including a wide bandgap, high breakdown voltage, exceptional chemical stability, and high thermal conductivity. These characteristics render GaN and AlN highly promising for use in power and (opto)-electronic devices. Consequently, there is a growing demand for high-quality GaN and AlN crystals on the centimeter scale. As the dislocation density in these materials decreases, the need for a reliable method of dislocation characterization becomes more pressing. Synchrotron radiation x-ray topography (SR-XRT) has emerged as a superior, nondestructive technique for the precise characterization of crystal defects. This review briefly introduced the principle of XRT, and its application in the analysis of dislocations in GaN and AlN crystals is summarized. By examining the relationship between the SR-XRT image contrast and the Burgers vectors of dislocations, it is possible to categorize wafer dislocations and determine the magnitude and direction of Burgers vectors. Additionally, SR-XRT facilitates the analysis of interactions between dislocations in GaN and AlN crystals. These analyses are instrumental in advancing the development of superior crystals. This review concludes with a discussion of the current challenges faced by SR-XRT and a projection of its future applications in characterizing third-generation semiconductor crystal materials. This review offers significant guidance for the characterization of nitride crystal defects using SR-XRT.

Prediction of the Structural, Mechanical, and Physical Properties of GaC: As a Potential Third-Generation Semiconductor Material.

Similar to GaN and SiC semiconductors, GaC may be a potential semiconductor because of the mixed elemental features of Ga and C. Unfortunately, the phase stability and mechanical and physical properties of GaC are unknown. To search for novel third-generation semiconductors, the present study delves into an in-depth analysis of the structural stability and electronic and optical properties of GaC by DFT calculations. Similar to GaN, three GaC phases are discussed. It is found that three GaC phases (two cubic phases and one hexagonal phase) are first predicted. The band gaps of Fm3̅m, F4̅3m, and hexagonal GaC are 0.449, 2.733, and 3.340 eV, respectively. In particular, the band gap of F4̅3m GaC and hexagonal GaC is bigger than that of GaN. Compared to GaN semiconductors, the C-2p state is in the valence band region across the Fermi level, which is beneficial to electronic mobility and electronic transport capacity near the Fermi level. In addition, three GaC phases exhibit ultraviolet properties. The first peak of three GaC phases produces the right migration compared to the GaN semiconductor. Therefore, the author predicts that GaC is a potential third-generation semiconductor material which is potentially used in future third-generation semiconductor industries.

High-efficiency green machining of single crystal 4H–SiC based on tribo-oxidation

High efficiency, high quality and green machining of single crystal silicon carbide (SiC) is an important issue in the third-generation semiconductor industry. In this paper, a novel machining method for single crystal SiC based on tribo-oxidation is proposed. The formula and preparation process of polysaccharide bonded soft abrasive tool were designed. Dry machining of C-face of 4H–SiC substrate was carried out with the prepared environmentally friendly abrasive tool sample. The material removal mechanism of the proposed machining method was preliminarily analyzed, and the material removal rate, surface roughness and subsurface residual stress were studied. The experimental results show that the maximum material removal rate of 4H–SiC can reach 1.03 μm/min with a corresponding average surface roughness of Sa 0.816 nm. The machined surface has no brittle flaw, and subsurface residual compressive stress exists with a maximum value of 58.9 MPa. The material removal mainly attributed to the active oxidation of SiC surface induced by the friction between alumina abrasives and SiC substrate. The proposed machining method has potential application value in thinning of SiC wafers.

Growth and properties of tantalum carbide coatings on graphite by TRD technique

The tantalum carbide-coated graphite material exhibits remarkable chemical stability, corrosion resistance, and heat shock resistance, enabling it to demonstrate excellent stability during the growth of wide bandgap semiconductors. Its application significantly enhances the quality of third-generation semiconductor crystals. Nevertheless, the high cost of this material hinders its widespread utilization in the field of wide bandgap semiconductors. To address this challenge, this study employs the Thermo-reaction deposition and diffusion (TRD) technique to successfully fabricate a tantalum carbide coating on the surface of graphite. Through thermodynamic analysis, this article validate the thermodynamic feasibility of preparing tantalum carbide coatings using the TRD process. To achieve a dense and uniform TaC coating on the graphite surface, we systematically investigate the effects of reducing agent content, reaction temperature, and reaction time on the microstructure of the coating. Experimental research has found that a molar ratio of B4C to Ta2O5 of 1:0.64 optimizes the coating uniformity. Deviations from this ratio, either higher or lower, can lead to coating inhomogeneity or even failure in coating formation. Additionally, this article determine that a reaction temperature range of 1200–1400 °C, coupled with a reaction time not exceeding 6 h, represents the most suitable conditions for preparing TaC coatings on the graphite surface. Finally, to evaluate the practical performance of the coated graphite, this article simulate the corrosive environment encountered during the physical vapor transport method for growing aluminum nitride single crystals. The results demonstrate a significant improvement in the corrosion resistance of the coated graphite. This enhancement is primarily attributed to the formation of a dense TaC coating on the graphite surface, which exhibits remarkable stability at elevated temperatures.

Critical state-induced emergence of superior magnetic performances in an iron-based amorphous soft magnetic composite

Soft magnetic composites (SMCs) play a pivotal role in the development of high-frequency, miniaturization and complex forming of modern electronics. However, they usually suffer from a trade-off between high magnetization and good magnetic softness (high permeability and low core loss). In this work, utilizing the order modulation strategy, a critical state in a FeSiBCCr amorphous soft magnetic composite (ASMC), consisting of massive crystal-like orders (CLOs, ∼1 nm in size) with the feature of α-Fe, is designed. This critical-state structure endows the amorphous powder with the enhanced ferromagnetic exchange interactions and the optimized magnetic domains with uniform orientation and fewer micro-vortex dots. Superior comprehensive soft magnetic properties at high frequency emerge in the ASMC, such as a high saturation magnetization (M s) of 170 emu g−1 and effective permeability (μ e) of 65 combined with a core loss (P cv) as low as 70 mW cm−3 (0.01 T, 1 MHz). This study provides a new strategy for the development of high-frequency ASMCs, possessing suitable comprehensive soft magnetic performance to match the requirements of the modern magnetic devices used in the third-generation semiconductors and new energy fields.

Synergistic effect of abrasive friction and glycine on improving chemical mechanical polishing performance of single-crystal GaN substrate

With the rapid development of the third-generation semiconductor materials, the chemical mechanical polishing rate and surface quality of single-crystal gallium nitride (GaN) substrates have been a research hot-spot. In this work, the synergistic effect of abrasive friction and glycine (Gly) on improving the chemical mechanical polishing (CMP) performance of single-crystal GaN substrate is proposed and studied systematically. The results indicated that the polishing solutions with Gly have a 2.3-fold improvement in material removal rate (MRR) as well as scratch-free surface than that without Gly. The maximum MRR of the single-crystal GaN substrate is 129.4 nm/h with surface roughness (Ra) of 0.64 nm attained by using the polishing solutions containing only 3 wt% potassium persulfate (K2S2O8). In contrast, when Gly is added as a reaction reagent, which can be activated by abrasive friction, the maximum MRR is increased to 304.2 nm/h with Ra of 0.42 nm. Meanwhile, the epitaxial evaluation indicates that two-dimensional (2D) MoS2 grown on processed single-crystal GaN substrate has superior crystalline quality and optical properties. Finally, the polishing mechanism of the single-crystal GaN substrate using the mixed solutions of K2S2O8 and Gly is discussed. The proposed CMP method has potential applications in the semiconductor and microelectronics industries.

Third generation semiconductor device research: Optimizing CMOS and HEMT designs

The third-generation semiconductor device known as High Electron Mobility Transistors (HEMT) has found extensive applications in high-frequency and high-speed electronic systems. Its widespread usage in critical technologies such as radio telescopes, satellite broadcast receivers, and cellular base stations has established HEMT as a foundational technology underpinning our information and communication society. This paper provides an in-depth exploration of these semiconductor advancements. Firstly, the paper utilizes the CMOS inverter as a representative example to elucidate the fundamental structure of Complementary Metal-Oxide-Semiconductor (CMOS) technology. Additionally, it employs Gallium Arsenide (GaAs) HEMT as an illustrative instance to expound upon the architecture of HEMT devices. Furthermore, the paper delves into the optimization of CMOS technology, focusing on topics such as Multi-Threshold CMOS and the impact of the Width/Length (W/L) ratio. These discussions shed light on ways to enhance the performance of CMOS-based components. Additionally, the paper explores strategies to optimize HEMT devices, including the introduction of carbon doping and the application of the Grey-Wolf optimization technique. These approaches are critical in achieving higher efficiency and performance in HEMT-based applications.

Polishing Mechanism of CMP 4H-SiC Crystal Substrate (0001) Si Surface Based on an Alumina (Al2O3) Abrasive.

Silicon carbide, a third-generation semiconductor material, is widely used in the creation of high-power devices. In this article, we systematically study the influence of three crucial parameters on the polishing rate of a silicon carbide surface using orthogonal experiments. By optimizing the parameters of chemical mechanical polishing (CMP) through experiments, we determined that the material removal rate (MRR) is 1.2 μm/h and the surface roughness (Ra) is 0.093 nm. Analysis of the relevant polishing mechanism revealed that manganese dioxide formed during the polishing process. Finally, due to the electrostatic effect of the two, MnO2 adsorbed on the Al2O3, which explains the polishing mechanism of Al2O3 in the slurry.

Photoelectric properties of two-dimensional electron gas at the (Ga0.5Al0.5)2O3/SrTiO3 heterointerfaces

We report a two-dimensional electron gas created at the (Ga0.5Al0.5)2O3/SrTiO3 heterointerfaces with different deposition temperatures and thicknesses by a pulsed laser deposition method. It is found that the critical deposition temperature for the metal-to-insulator transition is about 400 °C with a thickness of 43.2 nm. The carrier density and mobility of sample at the deposition temperature of 300 °C are 1012 cm−2 and 67.2 cm2 V−1 s−1 at 50 K, respectively. The thickness of the conductive layer is ∼4.0 nm estimated from the anisotropic magnetoresistance. The bandgaps of films deposited at different temperatures are in the range of 5.6–5.9 eV. Furthermore, the heterointerfaces have a strong response to 360 nm light with a relative resistance change of ∼70%. Our results are related to the charge transfer due to the oxygen defect at the interfaces, which provides a way for the development of third-generation semiconductor optoelectronic devices.

Advancements And Prospects in Third-Generation Semiconductor Materials: A Comprehensive Analysis

This paper provides an in-depth exploration of the advancements, applications, and future prospects of third-generation semiconductor materials, focusing primarily on Silicon Carbide (SiC) and Gallium Nitride (GaN). It begins with a detailed discussion on the theoretical basis of semiconductor materials, highlighting the limitations of silicon semiconductors and the emergence of wide bandgap semiconductors as a superior alternative. The paper then delves into the diverse application scenarios of SiC and GaN, underscoring their significant roles in fields ranging from automotive and photovoltaics to high-frequency telecommunications and military technologies. Subsequent sections address the inherent challenges and ongoing improvements in the field, particularly in terms of defect management, cost reduction, and technological enhancements in device fabrication. The paper concludes with an optimistic outlook on the future of these materials, envisioning their pivotal role in transforming power electronics through improved efficiency and performance. This comprehensive review not only elucidates the current state of third-generation semiconductors but also anticipates their impact on future technological developments.

Comparative Analysis of Sic and Gan: Third-Generation Semiconductor Materials

This article delves into a comprehensive comparative analysis of two prominent third-generation semiconductor materials, silicon carbide (SiC) and gallium nitride (GaN). It explores their foundational theories, practical applications, future prospects, and the hurdles they face in the realm of materials science. SiC is characterized by its impressive thermal conductivity and a wide bandgap, while GaN showcases remarkable electron mobility and high electron saturation velocity. Both materials have demonstrated outstanding capabilities in high-temperature, high-frequency, and high-power electronic devices, finding utility in power conversion, automotive systems, and optoelectronics. Looking forward, SiC and GaN hold tremendous potential in emerging fields such as new energy sources, advanced optoelectronic devices, and semiconductor packaging. Nevertheless, they encounter challenges, including manufacturing costs and the control of crystal defects. In conclusion, these third-generation semiconductors offer extensive possibilities across various domains, although overcoming significant challenges is essential for their widespread integration.

Unlocking The Potential of Gallium Nitride (Gan) For Third-Generation Semiconductors: Advantages, Applications, And Future Prospects

Wide-bandgap materials, exemplified by gallium nitride (GaN), are poised to elevate electronic performance to new heights. This paper is focus on the third-generation semiconductor which is considered as the most promising semiconductor. The first section will discuss the fundamentals of CMOS and HEMT, including their construction, operation, benefits, and properties. The two are next be compared, and it is revealed that although GaN has some limitations on its cost and manufacture, it also having higher energy gap, compact size, higher efficiency, lower switching losses. Meeting the increasingly rigorous requirements associated with high power and high-density applications requires the use of these advantages. Then, using examples from the aerospace, mobile phone chargers, and LiDAR fields, applications of GaN HEMTs are discussed. The issues and prospects for third generation semiconductors are finally went over. It shows significant potential for energy efficiency benefits in infrastructure, and it is intriguing to see how the new semiconductor generation develops in the next few years.

Atomic layer deposition and application of group III nitrides semiconductor and their alloys

Group III nitride semiconductors, such as GaN, AlN, and InN, are an important class of compound semiconductor material, and have attracted much attention, because of their unique physicochemical properties. These semiconductors possess excellent characteristics, such as wide direct bandgap, high breakdown field strength, high electron mobility, and good stability, and thus are called third-generation semiconductors. Their alloy materials can adjust their bandgaps by changing the type or proportion of group III elements, covering a wide wavelength range from near-ultraviolet to infrared, thereby achieving wavelength selectivity in optoelectronic devices. Atomic layer deposition (ALD) is a unique technique that produces high-quality group III nitride films at low temperatures. The ALD has become an important method of preparing group III nitrides and their alloys. The alloy composition can be easily controlled by adjusting the ALD cycle ratio. This review highlights recent work on the growth and application of group III nitride semiconductors and their alloys by using ALD. The work is summarized according to similarities so as to make it easier to understand the progress and focus of related research. Firstly, this review summarizes binary nitrides with a focus on their mechanism and application. In the section on mechanism investigation, the review categorizes and summarizes the effects of ALD precursor material, substrate, temperature, ALD type, and other conditions on film quality. This demonstrates the effects of different conditions on film growth behavior and quality. The section on application exploration primarily introduces the use of group III nitride films in various devices through ALD, analyzes the enhancing effects of group III nitrides on these devices, and explores the underlying mechanisms. Additionally, this section discusses the growth of group III nitride alloys through ALD, summarizing different deposition methods and conditions. Regarding the ALD growth of group III nitride semiconductors, there is more research on the ALD growth of AlN and GaN, and less research on InN and its alloys. Additionally, there is less research on the ALD growth of GaN for applications, as it is still in the exploratory stage, while there is more research on the ALD growth of AlN for applications. Finally, this review points out the prospects and challenges of ALD in preparation of group III nitride semiconductors and their alloys.

New generation copper-based interconnection from nanoporous CuSn alloy film sintered at low temperatures

Two-step routine for the synthesis of nanoporous CuSn alloy material enabling joint formation in electronic packaging by sintering at 180 °C.