单晶硅衬底异质外延3C-SiC薄膜研究进展

3C-SiC薄膜的外延生长一直是SiC材料制备领域的一个热点,单晶Si衬底异质外延3C-SiC是实现大尺寸、低成本薄膜的有效方法,备受人们关注.单晶Si与3C-SiC之间存在较大的晶格失配(20％)和热膨胀系数差异(8％),严重制约着高质量单晶薄膜的制备.本文对单晶Si衬底异质外延3C-SiC薄膜的基本原理和工艺过程进行了总结,着重介绍了薄膜生长中的缺陷和可控掺杂方面的研究进展以及面临的挑战,并对今后的研究热点做了归纳展望.     

物理气相传输法SiC衬底上生长AlN单晶的研究进展

氮化铝(AlN)是直接带隙半导体，具有超宽禁带宽度(6.2 eV)、高热导率[3.2 W/(cm·K)]、高表面声波速率(V_L=10.13×10⁵ cm/s,V_T=6.3×10⁵ cm/s)、高击穿场强和稳定的物理化学性能，是紫外/深紫外发光材料的理想衬底，由此制作的Al_xGa_1–xN材料，还可以实现200～365 nm波段内的连续发光；可以制作耐高压、耐高温、抗辐射和高频的电子器件，是具有巨大潜力的新一代半导体材料。本文介绍了物理气相传输法异质外延生长AlN单晶的原理，并从碳化硅(Si C)衬底上AlN单晶生长研究历程、Al N/SiC衬底生长AlN晶体以及偏晶向SiC衬底生长AlN晶体3个方面综述了SiC衬底上异质外延生长AlN晶体的研究进展。最后简述了SiC衬底上生长AlN单晶面临的挑战和机遇，展望了AlN材料的未来发展前景。     

第三代半导体生产应用“四高两涂”碳基材料的技术现状

近年来,PVT生长SiC单晶方面取得了显著的进展。SiC粉是PVT法生长SiC单晶原料,其纯度会影响单晶质量,而C粉纯度决定SiC粉纯度;高纯硬毡、高纯石墨是生长单晶设备的必备组件,决定着PVT设备使用性能;SiC涂层、TaC涂层为石墨制品的保护涂层,保护晶体生长过程中不被污染。本文主要介绍了“四高两涂”的制备方法及研究现状。     

我国半导体SiC单晶粉料和设备生产实现新突破

正近日,在中国电子科技集团公司第二研究所(简称中国电科二所),100台碳化硅(SiC)单晶生长设备正在高速运行,SiC单晶就在这100台设备里"奋力"生长。SiC单晶是第三代半导体材料,以其特有的大禁带宽度、高临界击穿场强、高电子迁移率、高热导率等     

PVT法制备SiC单晶的研究进展

碳化硅（SiC）作为第三代半导体材料,具有相比于第一、二代半导体更优异的特性,在微电子、光电子等领域有着重要的应用价值。制备得到高质量、大尺寸的SiC单晶是实现其产业应用的前提。PVT法生长SiC单晶是现今的主流生长方法。总结了PVT法生长SiC单晶的四个主要影响因素的研究进展,拟在寻找未来的研究和发展方向。     

无微管缺陷六英寸SiC单晶的制备EI北大核心CSCD

SiC单晶衬底中的微管缺陷对SiC基器件是一种致命的缺陷,会严重影响SiC功率器件的成品率.基于物理气相传输(PVT)法,通过改进生长设计装配制备了绝对零微管缺陷6 in的n型4H-SiC单晶.从结晶学和动力学原理对改进生长设计装配消除微管的机理进行分析,阐明了单晶生长过程中微管分解和闭合的机制.采用的优化生长设计方案不仅有利于提高SiC单晶生长的稳定性,更可以提高SiC单晶的结晶质量,达到快速降低微管缺陷目的.所制备的无微管缺陷、大尺寸6 in n型4H-SiC单晶更加适合制作高压以及特高压功率器件.     

无微管缺陷六英寸SiC单晶的制备

SiC单晶衬底中的微管缺陷对SiC基器件是一种致命的缺陷,会严重影响SiC功率器件的成品率。基于物理气相传输(PVT)法,通过改进生长设计装配制备了绝对零微管缺陷6in的n型4H-SiC单晶。从结晶学和动力学原理对改进生长设计装配消除微管的机理进行分析,阐明了单晶生长过程中微管分解和闭合的机制。采用的优化生长设计方案不仅有利于提高SiC单晶生长的稳定性,更可以提高SiC单晶的结晶质量,达到快速降低微管缺陷目的。所制备的无微管缺陷、大尺寸6inn型4H-SiC单晶更加适合制作高压以及特高压功率器件。     

日本高技术陶瓷的近况

高技术陶瓷是９０年代人们所注目的功能材料和工程材料，是继金属塑料之后的第三大类的材料体系，常为多晶烧结体，也包括单晶，薄膜或纤维结构，本文介绍了日本高技术陶瓷的产业群，功能陶瓷技术，工程陶瓷技术以及它们的应用技术。     

水热法制备陶瓷材料研究进展

本文综述了水热法在单晶生长、粉体制备、薄膜、纤维制备、材料合成与处理等方面的研究进展。     

SrTiO3薄膜的自组装生长

利用激光分子束外延技术在LaAlO3(100)单晶基片表面生长SrTiO3(STO)薄膜。通过反射式高能电子衍射原位实时监测STO薄膜自组装生长过程，采用原子力显微镜分析自组装生长演化过程，并利用X射线衍射分析薄膜结构及其生长方向。对不同生长条件下薄膜的生长的研究发现：在较低生长温度时，STO薄膜在(200)方向上以三维岛状模式进行生长，小岛在单位原胞尺度呈波浪状周期性排列，即出现自组装生长；而在较高的生长温度时，薄膜以层状模式进行生长自组装行为被抑止。并据此讨论了STO多元氧化物薄膜自组装生长条件及生长机理。     

铝在硫酸溶液中的复合阳极氧化研究Ⅲ难溶粉体预处理对阳极氧化的影响

采用常规方法研究了SiC难溶粉体分别经酸、碱、表面活性剂三种溶液预处理后，对铝在硫酸溶液中复合阳极氧化的影响，实验结果表明：预处理后的SiC粉体不影响阳极氧化过程，而影响阳极氧化时的槽电压与膜层性能，经碱处理后的SiC粉体，效果最好，槽电压和膜层性能提高。     

SMA-纳米SiC及SMA-纳米金刚石复合膜制备及其Cu2+离子吸附性能

以纳米SiC及纳米金刚石粉体为添加剂,通过苯乙烯与顺丁烯二酸酐的聚合,成功制备了苯乙烯-马来酸酐-纳米碳化硅(SMA-纳米SiC)及苯乙烯-马来酸酐-纳米金刚石(SMA-nano diamond)复合薄膜材料。通过热重分析(TG)、傅里叶红外光谱仪(FTIR)和扫描电子显微镜(SEM)对吸附复合膜的结构进行表征。研究了SMA-纳米SiC及SMA-纳米金刚石复合膜的吸水性及其对二价铜(Cu²⁺)离子的吸附特性。结果表明,无机纳米颗粒的添加均提高了复合薄膜的耐热特性,提高了热分解温度。当纳米粉体含量在0.8~1.2 g之间,可以获得较为均匀的泡沫状多孔复合薄膜。浸泡6 h,纳米SiC添加量为1.0 g的复合膜吸水率低至4.81%。纳米金刚石添加量为1.0 g,复合膜吸水率低至3.52%。适量的纳米SiC及纳米金刚石可以提高复合膜的耐水性能。SMA-纳米SiC及SMA-纳米金刚石复合膜材料均对Cu²⁺离子具有一定的吸附特性,泡沫状复合膜吸附性能最佳。纳米SiC及纳米金刚石能够有效改善SMA膜对重金属离子的吸附性能。     

Enhanced thermal stability by introducing TiN diffusion barrier layer between W and SiC

The combination of W and SiC has many applications such as a hot cell of a thermionic energy converter, nuclear material, and high temperature microelectronics. In this study, a 2 µm thick TiN film is introduced as a diffusion barrier between SiC and W to avoid the inter-diffusion reaction at high temperature. The effect of annealing temperature on the surface morphology and microstructure of the TiN film is studied to explore its high temperature stability. Then 500 nm W film is sputtered on the TiN film to characterize the inter-diffusion and stability of the W/TiN/SiC multilayer at 1100°C by XRD, Raman spectroscopy and cross-sectional EDS mapping techniques. The results indicate that the W/TiN/SiC multilayer is very stable even when heated at 1100°C for 25 hours.     

Controlling the electrical resistivity of porous silicon carbide ceramics and their applications: A review

Porous silicon carbide (SiC)-based ceramics are widely used in numerous applications of technical importance owing to their exceptional structural (e.g., excellent chemical, mechanical, and thermal stability) and functional (e.g., controlled electrical resistivity) properties. Porous SiC with controlled electrical resistivity is required for various advanced applications, for example, power electronic devices, semiconductor processing parts, fusion reactors, thermoelectric energy conversion, electromagnetic shielding, and environmental applications such as heatable filters. The electrical properties of sintered porous SiC are significantly affected by its chemical composition, processing conditions, and microstructure. This article reviews the influence of certain critical factors, such as the polytype, doping conditions, porosity (%), additive composition (oxide additives, element additives, metal nitride/carbide additives, etc.), and processing conditions on the electrical resistivity of porous SiC. Novel applications of porous SiC with controlled electrical resistivity are also discussed in this review.     

Effects of Interfacial Films on Thermal Stresses in Whisker-Reinforced Ceramics

Toughening of whisker-reinforced (or fiber-reinforced) ceramics by whisker pullout requires debonding at the whisker/matrix interface. Compressive clamping stresses, which would inhibit interface debonding and/or pullout, are expected in composites where the matrix has a higher thermal expansion coefficient than the whisker. Because such mismatch in thermomechanical properties can result in brittle composites, it is important to explore approaches to modify the thermal stresses in composites. As a result, the effects of a film at the whisker/matrix interface on the stresses due to thermal contraction mismatch upon cooling are considered in this study. Analysis of various properties of the film are considered for the whisker/matrix systems, in particular for SiC/Al₂O₃, SiC/cordierite, and SiC/mullite composites. Reduction of thermomechanical stresses is shown to occur when the interfacial film has a low Young's modulus. Also, when the whisker has a lower thermal expansion coefficient than the matrix (e.g., SiC/Al₂O₃), the interfacial stresses generated during cooling decrease as the thermal expansion coefficient of the film increases.     

Synthesis,properties, and multifarious applications of SiC nanoparticles: A review

The development of particulate materials is accelerating at a tremendous speed and nanoparticles have gradually gained worldwide attention. Among them, silicon carbide (SiC) nanoparticles have attracted much attention due to their excellent performance and great application potential. This article mainly presents a comprehensive overview on the synthesis, properties and potential applications of SiC nanoparticles. Firstly, various synthesis techniques for SiC nanoparticles were discussed, with the classification of solid phase, liquid phase and vapor phase processes. Subsequently, the unique properties of SiC nanoparticles such as surface properties, thermal properties, electrical properties and biocompatibility properties were highlighted. Thereafter, diversified applications of SiC nanoparticles including composites, catalysts, fluorescent biological labels, bioadhesives and flexible field emitters have been discussed. Finally, contents of the article were summarized and outlooks of future research were stated.     

Performance optimization of Si/SiC ceramic triply periodic minimal surface structures via laser powder bed fusion

SiC ceramic lattice structures (CLSs) via additive manufacturing (AM) have been recognized as potential candidates in engineering fields owing to their various merits. Compared with traditional SiC CLSs, SiC triply periodic minimal surface (TPMS) CLSs could possess more outstanding properties, making them more promising for wider applications. Since SiC CLSs are hard to be fabricated through stereolithography techniques because of inferior light performance, the laser powder bed fusion (LPBF) process via selective sintering is an effective method to prepare near-net-shaped SiC TPMS lattices. As the mechanical performances of lattice structures are the foundation for future practical applications, it is of great significance to optimize the preparation process, thus improving the mechanical properties of SiC TPMS structures. In this work, the optimal printing parameters of the LPBF and liquid silicon infiltration process for SiC ceramic TPMS CLSs with three different volume fractions were systematically illustrated and analyzed. The effects of the printing parameters and carbon densities on the fabrication accuracy, microstructure, and mechanical performance of SiC TPMS CLSs were defined. The mechanism of the reactive sintering process for the SiC TPMS lattice structure was revealed. The results reveal that Si/SiC TPMS CLSs with optimum preparation have superior manufacturing accuracy (most less than 6%), relatively high bulk densities (about 2.75 g/cm³), low residual Si content (6.01%), and excellent mechanical properties (5.67, 15.4, and 44.0 MPa for Si/SiC TPMS CLSs with 25%, 40%, and 55% volume fractions, respectively).     

Flexible SiC-CNTs hybrid fiber mats for tunable and broadband microwave absorption

Flexible microwave absorbers with high stability are in increasing demand for the applications under harsh conditions. SiC as a functional ceramic material has the feature of high environmental tolerance and adjustable electromagnetic (EM) absorbing properties, making them suitable to be applied for harsh environments. However, the electrical property of SiC requires to be further enhanced to obtain qualified EM absorbing performance. In this work, multiwall carbon nanotubes (CNTs) were introduced to SiC to enhance the electrical properties. Flexible two-dimensional (2D) CNTs loaded SiC fiber mats were prepared as EM absorbers via electrospinning and polymer-derived-ceramic (PDC) methods. The CNTs inside the fibers can form conductive networks and act as reinforcement to ensure high flexibility and enhance the microwave absorption properties of SiC mats. Thus, a reflection loss of ?61 dB and an effective absorption band (EAB) of 2.9 GHz were obtained. More importantly, the EM absorption can be adjusted by tuning the content of CNTs and the EAB can cover the entire X-band by adjusting the material thickness. The work provided a facile strategy to fabricated flexible 2D ceramic mats with high environmental stability and tunable electrical properties, which may shed light on the production of reliable EM absorber for broadband EM absorption applications.     

Advances in modifications and high-temperature applications of silicon carbide ceramic matrix composites in aerospace: A focused review

This article is a detailed review of the measures to modify the high-temperature mechanical properties of silicon carbide ceramic matrix composites (SiC CMCs), namely toughness, high-temperature stability and wear resistance. Additionally, it briefly describes the common processing methods of the SiC CMCs and their application in the high-temperature field of aerospace. The advantages and disadvantages of various existing processing and molding methods for the SiC CMCs are also discussed. The high-temperature mechanical properties of the SiC CMCs are mainly affected by the properties of the matrix, added phase and interface. It is crucial to reduce the crystal defects of the matrix and select a suitable enhancement phase for an elevated performance. Moreover, it is important to improve the bonding at the interface between the enhancement phase and the matrix. This review is expected to provide useful information for the subsequent development of complex SiC CMCs for high-temperature applications.     

泡沫碳化硅陶瓷材料的研究进展

泡沫碳化硅陶瓷材料除了孔隙率高、比表面积大,还具有相对密度小、优良的热学、力学、电学、声学性能等特性,已经广泛应用于化工、机械、生物、环保等领域。本文总结了泡沫碳化硅陶瓷材料的主要制备技术,包括粉末烧结法、固相反应烧结法、含硅树脂热解法以及气相沉积法等。阐述了泡沫碳化硅陶瓷材料的几种优良特性,包括结构特征、流体阻力、抗氧化性、吸波性等。最后举例介绍了该陶瓷在催化、过滤、生物学等领域的应用现状,重点介绍了其作为塔内件在化工领域中的应用,指出为满足对泡沫碳化硅陶瓷更高性能的需求,不仅要对现有技术进行集成创新,更要挖掘和开发泡沫碳化硅的潜在优势。