宽禁带半导体SiC的离子束合成,掺杂隔离与智能剥离

碳化硅作为新一代宽禁带半导体材料，在高温、高频、高功率、抗辐照电子器件中有着十分广阔的潜在应用前景．文章结合作者的工作，综述了离子束技术在ＳｉＣ研究中的应用，其中包括ＳｉＣ的合成、掺杂、器件隔离和智能剥离．     

红外焦平面技术的重要进展──单片式SiGe红外焦平面阵列的物理基础和关键技术

由ＳｉＧｅ合金与Ｓｉ构成的应变层异质结构、量子阱是８０年代中期发展起来的一种新型半导体材料。本文着重讨论了单片式ＳｉＧｅ红外焦平面阵列的物理基础、高质量ＳｉＧｅ材料的制备以及低温ＳｉＧｅ器件研制中的几个关键技术。     

红外焦平面技术的重要进展—单片式SiGe红外焦平面阵列的物理基础和关键技

由ＳｉＧｅ合金与Ｓｉ构成的应变层异质结构、量子阱是８０年代中期发展起来的一种新型半导体材料。本文着重讨论了单片式ＳｉＧｅ红外焦平面阵列的物理基础、高质量ＳｉＧｅ材料的制备以及低温ＳｉＧｅ器件研制中的几个关键技术。     

SiGe ECL电路时间延迟分析

为保证 ＥＣＬ具有更好的电路性能,低温下制备 ＳｉＧｅ ＨＢＴ作为基本器件的 ＳｉＧｅ ＥＣＬ电路更适于低温应用,且传输延迟时间更小．１引言 ＳｉＧｅ ＥＣＬ电路是目前国际研究前言,在高速 ＣＰＵ、卫星通讯等领域有较高应用价值,在国内军事领域也将会有应用前景［１］ 采用ＳｉＤｅ ＨＢＴ作为ＥＣＬ电路单管可实现更低延迟时间单元电路［２］．为保证ＥＣＬ单元电路具有较快速度,ＳｉＤｅ ＨＢＴ需采用超薄基区、低发射区掺杂高基区掺杂等新型结构［３,４］． 从基尔霍夫方程出发,可对ＥＣＬ对管延迟时间作较为精确的推导．ｔ…     

散射理论方法应用于重构的β—SiC（100）表面

用Ｐｏｌｌｍａｎｎ散射理论方法分别计算理想的和重构的β－ＳｉＣ（１００）表面带结构以及层和原子轨道态密度。结果表明，重构的主要影响发生在禁区内，重构的Ｓｉ和Ｃ截断表面都具有半导体性，并且得到的表面带与相符。     

呼之欲出的新一代MOS栅极电介质材料

传统的ＳｉＯ２栅极电介质材料无法克服ＭＯＳ年特征尺度缩小带来的量子隧穿效应的影响,作为进上步提高微电子器件集成度的途径,利用新一代具有高介电常数的栅极电介质材料取代ＳｉＯ２的研究工作已经展开,文中介绍了此类材料抑制隧穿效应的原理和其应当满足的各项性能指标,并对目前几种主要的研究方案,如几种高介电常数金属氧化物、硅酸盐及其迭层结构的研究状况和优缺点给予也简要评述。     

散射理论方法应用于重构的β-SiC(100)表面

用Ｐｏｌｍａｎｎ散射理论方法分别计算了理想的和（２×１）重构的β-ＳｉＣ（１００）表面带结构以及层和原子轨道态密度．结果表明，重构的主要影响发生在禁区内，重构的Ｓｉ和Ｃ截断表面都具有半导体性，并且得到的表面带与实验相符．由二聚原子的成键和悬挂键的局域态密度定性地解释了二聚Ｓｉ原子的非对称性和二聚Ｃ原子的对称性     

非晶态半导体／金属薄膜的分形晶化

本文综述非晶态半导体／金属薄膜退火过程中金属诱导非晶态半导体晶化的研究,综述对若干非晶态半导体与金属组成的薄膜（Ｇｅ－Ａｕ、Ｇｅ－Ａｇ、Ｇｅ－Ａｌ、Ｇｅ－Ｓｅ、Ｇｅ－ｐｄ、Ｓｉ－Ａｇ、Ｓｉ－Ａｌ、Ｓｉ－ｐｄ、Ｓｉ－Ｃｕ、ｓｉｃ－Ａｌ、Ｓｉ＿３Ｎ＿４－Ａ１）晶化后形成的图形进行的分形研究,内容包括分形形成的实验规律、根据微结构电镜观测结果提出的随机逐次成核模型、以及对分形晶化进行的计算机模拟。     

非晶态半导体／金属薄膜的分形晶化

本文综述非晶态半导体／金属薄膜退火过程中金属诱导非晶态半导体晶化的研究，综述对若干非晶态半导体与金属组成的薄膜（Ｇｅ－Ａｕ、Ｇｅ－Ａｇ、Ｇｅ－Ａｌ、Ｇｅ－Ｓｅ、Ｇｅ－ｐｄ、Ｓｉ－Ａｇ、Ｓｉ－Ａｌ、Ｓｉ－ｐｄ、Ｓｉ－Ｃｕ、ｓｉｃ－Ａｌ、Ｓｉ＿３Ｎ＿４－Ａ１）晶化后形成的图形进行的分形研究，内容包括分形形成的实验规律、根据微结构电镜观测结果提出的随机逐次成核模型、以及对分形晶化进行的计算机模拟。     

21世纪的光学和光电子讲座第二讲 硅基发光材料和器件研究

硅基发光材料和器件是实现光电子集成的关键。文章评述了目前取得较大进展的几种主要硅基发光材料和器件的研究,包括掺饵硅,多孔硅,纳米硅以及Ｓｉ／ＳｉＯ２等超晶格结构材料,展望了这些不同硅基发光材料作为发光器件和在光电集成中的发展前景。     

The stability of SiC coating and SiO2/SiC multilayer on the surface of graphite for HTGRs at normal service condition

The stability of SiC coating in helium with a low concentration of O₂, CO₂, and H₂O is a key factor for their application in improvement of oxidation resistance of graphite for high temperature gas-cooled reactors (HTGRs). Through thermodynamic analysis, it is found that the influence factor controlling the critical temperature of passive oxidation for SiC is partial pressure of active gas in helium; the critical temperature of passive oxidation for SiC increases with the partial pressure of O₂, CO₂, and H₂O, SiC is prone to undergo active oxidation in He–CO₂ and He–H₂O system. SiO₂/SiC multilayer coating can improve the oxidation resistance of graphite at higher temperature than SiC coating does under normal operation condition for HTGRs.     

Raman investigation of defective SiC nanocrystals

Phonon confinement effect and surface optical mode in SiC nanocrystal have been investigated through Raman spectroscopy. Considering high density of stacking faults in SiC grains, the correlation length of RWL (proposed by Richter, Wang, Li to explain phonon confinement in nano silicon) model is determined as a distance between nearby stacking faults. Thus, homogeneous region becomes thin slices in cylindrical SiC grains, which redefines weighting function. Effect of anisotropy of phonon dispersion curve is also analyzed during calculation. The additional 875‐cm⁻¹ band is attributed to defects and amorphous SiC, which is confirmed by transmission electron microscopy. SiC grains are approximated as column array with grain boundary substances regarded as surrounding medium, which explains surface optical phonon mode at 915 cm⁻¹. Copyright © 2015 John Wiley & Sons, Ltd.     

氢氟酸刻蚀对Ni/6H-SiC接触性质的作用

采用浓度为10%的氢氟酸（HF）刻蚀6H-SiC单晶片,研究了HF刻蚀时间对Ni/6H-SiC接触性质的影响．经24?h刻蚀的SiC基片在溅射Ni层后,其接触表现良好线性的电流-电压（I-V）曲线．低于这个腐蚀时间的接触具有明显的势垒,但在大于1000℃快速退火后,也得到了良好线性的I-V曲线．X射线衍射（XRD）和俄歇能谱（AES）深度元素分析表明Ni₂Si和C是快速退火后的主要产物．XRD和低能反射电子能量损失谱表明表层的C 关键词： 欧姆接触 SiC 富碳层 互扩散     

Comparative study of high temperature anti-oxidation property of sputtering deposited stoichiometric and Si-rich SiC films

Stoichiometric and silicon-rich (Si-rich) SiC films were deposited by microwave electron cyclotron resonance (MW-ECR) plasma enhanced RF magnetron sputtering method. As-deposited films were oxidized at 800 ℃, 900 ℃, and 1000 ℃ in air for 60 min. The chemical composition and structure of the films were analyzed by x-ray photoelectron spectroscopy (XPS), Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR). The surface morphology of the films before and after the high temperature oxidation was measured by atomic force microscopy. The mechanical property of the films was measured by a nano-indenter. The anti-oxidation temperature of the Si-rich SiC film is 100 ℃ higher than that of the stoichiometric SiC film. The oxidation layer thickness of the Si-rich SiC film is thinner than that of the stoichiometric SiC film in depth direction. The large amount of extra silicon in the Si-rich SiC film plays an important role in the improvement of its high temperature anti-oxidation property.     

拉曼光谱方法研究SiC晶体的晶型

本文采用拉曼光谱方法对改进Lely生长法制备的SiC单晶的结构进行了分析,结果表明:晶体的结构为6H,样品的内部缺陷较多,其中存在4H-SiC。另外我们还测量了SiC晶体的高阶拉曼谱,并对其进行了分析归属。从分析结果来看拉曼光谱是研究SiC的晶体结构和生长质量有效快捷的方法。     

TiN/SiC纳米多层膜的生长结构与力学性能

研究了TiN/SiC纳米多层膜中立方SiC（B1cubic SiC）的形成及其对TiN/SiC多层膜力学性能的影响.结果表明：在TiN/SiC多层膜中，非晶态的SiC层在厚度小于0.6nm时形成立方结构并与TiN形成共格外延生长的超晶格柱状晶，使多层膜产生硬度和弹性模量显著升高的超硬效应，最高硬度超过60GPa.SiC随着层厚的增加转变为非晶相，从而阻止了多层膜的共格外延生长，使薄膜呈现TiN纳米晶和SiC非晶组成的层状结构特征，同时多层膜的硬度和弹性模量下降.TiN/SiC纳米多层膜产生的超硬效应与立方 关键词： 立方碳化硅 TiN/SiC纳米多层膜 外延生长 超硬效应     

聚合物前驱体制备层状SiC纳米棒的光学性质

采用聚硅氮烷前驱体在高温常压下热裂解方法制备了SiC纳米棒。透射电镜图表明SiC纳米棒中包含有独特的层状结构,电子能谱表明SiC纳米棒中的C ∶ Si组分比接近1 ∶ 1。用X射线衍射和喇曼光谱表征了SiC纳米棒的结构和成分,层状结构为6H-SiC和3C-SiC交替形成所致。利用光致发光谱在该层状结构中观察到强的紫外发射,认为强而锐的紫外发射峰是来源于厚度比较均一的6H-SiC层。     

Formation of epitaxial SiC nanocrystals

Epitaxial 3C-SiC grains are formed at 1190 °C in the top region of silicon, when Si wafers coated by SiO₂ are annealed in CO atmosphere. The formed SiC grains are 40-50 nm high and 100 nm wide in cross-section and contain only few defects. Main advantage of the method is that the final structure is free of voids.The above method is further developed for the generation of SiC nanocrystals, embedded in SiO₂ on Si, and aligned parallel with the interface. The nanometer-sized SiC grains were grown into SiO₂ close to the Si/SiO₂ interface by a two-step annealing of oxide covered Si: first in a CO, than in a pure O₂ atmosphere. The first (carbonization) step created epitaxial SiC crystallites grown into the Si surface, while the second (oxidation) step moved the interface beyond them. Conventional and high resolution cross-sectional electron microscopy showed pyramidal Si protrusions at the Si/SiO₂ interface under the grains. The size of the grains, as well as their distance from the Si/SiO₂ interface (peak of pyramids) can be controlled by the annealing process parameters. The process can be repeated and SiC nanocrystals (oriented in the same way) can be produced in a multilevel structure.     

Rectifying barrier at GaN/SiC hetero-junction studied with positron annihilation spectroscopy

Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This “rectifying” effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit （VEPF） analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.     

大口径轻质SiC反射镜的研究与应用

介绍了大口径轻质碳化硅反射镜镜坯的基本结构、性能测试指标、国内应用及发展前景;阐述了碳化硅凝胶注模成型（Gel-casting）、反应烧结SiC（RB-SiC）与压力成型、常压烧结SiC（SSiC）两种国内主要制备大口径轻质碳化硅反射镜的方法;并对两种方法制备得到的ø1.45 m碳化硅镜坯的性能、测试数据及光学加工后的光学特性进行分析和比对,提出存在的问题,以供商榷,进而促进国内大口径轻质碳化硅反射镜的研究和发展。