Silica to Silicon: Key Carbothermic Reactions and Kinetics

The primary carbothermic reactions for the reduction of silica to produce silicon were defined and the reaction kinetics were determined. Most possible reactions between silicon oxide and carbon or carbon compounds were studied by a series of thermogravimetric analyses at temperatures up to 2000°C. Four key sequential reactions occur with SiC and SiO as intermediate reactants; two reactions involve SiO₂ and two involve SiO. Reaction rate versus temperature, activation energy, and preexponential factors were determined for each of six reactions involving SiO₂ or SiO. These kinetic studies show that SiO, when combined with either carbon or Sic, reacts in the gaseous state, and the sublimation of SiO is not the rate-limiting reaction for forming silicon.     

Influence of different SiC surface treatments performed prior to Ni ohmic contacts formation

This work is dealing with the influence of surface treatment on ohmic contacts to hexagonal N-type SiC with medium doping level. The contact materials were Ni and Ni₂Si. The structures had to be annealed at high temperatures in order to reach ohmic behavior. A number of surface treatment methods were tested: wet cleaning, plasma etching, intentional oxidation with etching, H₂ annealing and their combinations. After some types of cleaning, the SiC surface was immediately analysed using the XPS method. The results of the analyses showed that the composition of the surface was not much influenced by these treatments. At lower annealing temperatures (approx. up to 850 °C) the prepared contacts showed Schottky behavior with large scatter of parameters. After annealing at approx. 960 °C, where the onset of ohmic behavior is expected, the structures were truly ohmic and of good parameters. Cleaning methods had just a negligible influence on the electrical parameters of the ohmic contacts. An explanation for these observed facts is suggested: Although - already on the basis of the XPS results - we could speak about a negligible influence of the cleaning onto the contact parameters, there might come across also other mechanisms coming from interaction of contact materials with SiC, which caused similar behavior of ohmic contacts on differently treated surfaces.     

Dislocation-mediated plasticity in silicon during nanometric cutting: A molecular dynamics simulation study

The nucleation and propagation of dislocations and its consequence on the defect structure in silicon during nanometric cutting are not well known, although the amorphization and high pressure phase transformation studies on silicon have remained at the epicentre of research across various disparate disciplines for over a decade. This paper proposes a new mechanism of crystal plasticity identified by a fully automated dislocation extraction algorithm in molecular dynamics simulations of nanometric cutting of silicon for different cutting planes/directions at a wide range of temperatures (300–1500 K). Alongside amorphization of silicon, our simulations revealed nanoscale stochastic nucleation of dislocations and stacking faults, which serve as mediators of microscopic plasticity during various contact loading operations and manufacturing processes of silicon. Of interest is that, irrespective of the cutting temperature, the stacking faults, which were not formed for either the (010)[100] or (111)[$\bar{1}1$0] crystal setups, were generated with three atomic layers in the (110)[00$\bar{1}$] cutting.     

Substrate issues for the growth of mercury cadmium telluride

Close lattice matching and lattice compatibility with mercury cadmium telluride (MCT) make CdTe and related alloys ideal substrate materials for growth of MCT layers for the purpose of making high-performance second-generation infrared detectors. However, the limitations in the properties of CdTe and the difficulties in its bulk growth have prompted extensive research in the area of alternative substrates. Some basic relevant characteristics of substrates such as sapphire, GaAs, and silicon are compared and the possibilities and problems associated with each material are analyzed in the light of the most recent results in the field.     

非氧化物陶瓷－金属接合及其机理

综述了近年来非氧化物陶瓷－金属接合的发展动态，概括了活性合金法非氧化物陶瓷－金属的接合机理。     

BeO瓷的金属化和封接

综述了氧化铍瓷的金属化及其封接技术,指出氧化铍瓷和Al2O3瓷在金属化工艺上的差异,论文最后汇集了国内外常用烧结金属粉末法15种配方和工艺参数,以资同行专家参考.     

标准CMOS工艺栅控Si-LED设计与制备

采用新加坡半导体制备有限公司的0.35um EEPROM双栅标准CMOS工艺设计和制备了U型Si-LED发光器件。器件结构采用P+-N+-P+-P+-P+-N+-P+-P+-P+-N+-P+叉指结构形成U型器件,外部的两个P+区为保护环,在相邻的内部两个P+区之间使用多晶硅作为栅极来调控LED的正偏发光。使用奥林巴斯IC显示镜测得了硅LED实际器件的显微图形,并对器件进行了电学的正反向I-V特性测量。器件在室温下正向偏置,在100～140mA电流下对器件进行了光功率的检测,发光峰值在1089nm处。结果表明,器件发光功率随着栅控电压偏置电流的增加而增加。     

晶体硅中缺陷和沉淀的红外扫描仪研究

晶体硅中的杂质或缺陷会显著地影响各种硅基器件的性能.通过红外扫描仪观察晶体硅中的晶界、位错和不同金属沉淀的分布和形貌,并分析其相关信息.与传统研究手段相比,红外扫描仪不仅可以直接观察到体内的缺陷或沉淀,而且不会破坏样品.     

直视芯式单模光纤熔接机微动机构

本文介绍了直视芯式单模光纤熔接机采用柔性铰链式微动机构的原理及构成,其调整精度可达到±0.1μm,使单模光纤熔接机的连接损耗大大降低。另外,还对其性能及指标与日本产品进行了比较。     

Design of unidirectional emission silicon/Ⅲ-Ⅴ laser for on-chip interconnects

We propose a unidirectional emission silicon/Ⅲ-Ⅴ laser,which comprises an Ⅲ-Ⅴ quantum wells microdisk connected to an output waveguide and a silicon-on-insulator (SOI) waveguide.Characteristics of the ...