Subsurface Damage in the Monocrystal Silicon Grinding on Atomic Scale

A molecular dynamics （MD） simulation is carried out to analyze the effect of cutting edge radius,cutdepth, and grinding speed on the depth of subsurface damage layers in monocrystal silicon grinding processes on an atomic scale. The results show that when the cutting edge radius decreases in the nanometric grinding process with the same cut-depth and grinding speed, the depth of the damage layers and the potential energy between the silicon atoms decrease too. Also, when the cut depth increases, both the depth of the damage layers and the potential energy between silicon atoms increase. When the grinding speed is between 20 and 200m/s,the depth of the damage layers does not change much with the increase of the grinding speed under the same cutting edge radius and cut depth conditions. This means that the MD simulation is not sensitive to changes in the grinding speed, and thus increasing the grinding speed properly can shorten the sion,the subsurface damage of monocrystal silicon is silicon atoms, which is verified by the ultra-precision simulation time and enlarge the simulation scale. In conclumainly based on the change of the potential energy between grinding and CMP experiments.

A CMOS Compatible MEMS Pirani Vacuum Gauge with Monocrystal Silicon Heaters and Heat Sinks

We present a micro-Pirani vacuum gauge using the low-resistivity monocrystal silicon as the heaters and heat sinks fabricated by the post complementary metal oxide semiconductor （CMOS） microelectromechanical system （MEMS） process. The metal interconnection of the device is fabricated by a 0.5 μm standard CMOS process on 8-inch silicon wafer. Then, a SiO2-Si low-temperature fusion bonding is developed to bond the CMOS wafer and the MEMS wafer, with the electrical connection realized by the tungsten through silicon via process. Wafer- level A1Ge euteetic bonding is adopted to package the Pirani gauge in a non-hermetic cavity to protect the gauge from being damaged or contaminated in the dicing and assembling process, and to make it suitable for actual applications. To increase the accuracy of the test and restrain negative influence of temperature drift, the Wheatstone bridge structure is introduced. The test results show that before capping, the gauge has an average sensitivity of 1.04 × 104 K.W-1Torr-1 in dynamic range of 0.01 20 Torr. After capping, the sensitivity of the gauge does not decrease but increases to 1.12 × 104 K.W-1 Torr-1.

A Mapping Technique to Draw Resistivity Isocontours for Slice-of-Silicon Monocrystal

A resistivity distribution with a space of 3mm between test points was measured on a slice-of-silicon monocrystal （diameter 75mm） using an inclined four-point probe. This paper has determined the number of resistivity divisions and their separations by statistical methods and introduced fuzzy mathematics to place the data into different fuzzy sets, after choosing the exponent function as a membership function for fuzzy sets and suitable values of thresholds. One fuzzy set corresponds to one resistivity isocontour. Then,the resistivity isocontours can be drawn with a definite separation and fi- nally shown in a map with MATLAB. The deviation of resistivity data on an isocontour is small and there are few residual test points without connections. So, the connection of the isocontours are high-quality and useful in application for instructing practical production.

Nitridation Kinetics of Silicon Monocrystal and Morphology of Nitride Film

Basing on TGA (thermal gravimetric analysis) of thermal nitridation at l200, l250, l300℃, respectively, analysis of high temperature kinetics for nitridation of silicon monocrystal has been carried out. According to the theory for kinetics of reaction of vapour with solid phase a nitridation kinetic model, from which it can be shown thal the rate of nitridation reaction of silicon crystal should be controlled by three stage limiting factors, was proposed. These limiting factors are chemical reaction, chemical reaction mixed with diffusion and diffu- sion. Using this model to treat our experimental data, satisfactory correlation coefficient and apparent activation energy of nitridation of p-type (lll) silicon crystal have been obtained. The nitride film was identi' fied to be a-Si_3N_4 (Hexagonal, a=0.7758nm,c_o=0.5623nm) by X-ray diffraction analysis. Morphology of the nitride films formed in different nitridation duration was observed in both planar andcross-sectional views by SEM (scanning electron microscope).

Oxidation Kinetics of (111) Silicon Monocrystal and Morphology of Oxide Film in Dry Oxygen Atmosphere

1. Introduction Thermal oxidation of silicon monocrystalis a very important process in fabricationof metal--oxide--semiconductor (MOS) devices.In recent years it has received great atten-tion. Various proposals for oxidation modeshave been made by different groups.Now most of the authors working in thisfield hold the view that the oxidation rateof silicon obeys a typical parabolic rule,that is, the oxidation reaction is controlledby diffusion. The experimental data inRef. can be taken and a kinetic curve

Stabilization of cubic ordering of zirconium dioxide nanoclusters on silicon with laser ablation

Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and atomic-force microscopy reveal that the coatings obtained are of nanocluster structure with the cubic ordering.In this case the nanoclusters reach several hundreds of nanometers in size.An assumption was made that on laser ablation of ZrO2 thermostabilization may take place where a minimum of the surface energy is attained just at cubic ordering.

The development and application of silicon Neutron Transmutation Doping (NTD) technology in China

The research and development history of silicon Neutron Transmutation Doping (NTD) technology and its applications at home and abroad are introduced in this paper.The advantages of NTD,compared with conventional technology of doping,are narrated.The principle of NTD as well as the implementation of the main procedures related to Si NTD is explained.The market demand tendency is prospected,and the advanced measures on NTD quality control are described.

单晶硅力学性能及尺寸效应的离散元模拟

通过建立紧密连接且随机分布在指定区域内的圆盘形颗粒离散单元的力学模型来研究单晶硅的力学性能,并采用不同尺寸的离散元模型研究力学性能尺寸效应。结果表明:泊松比、单轴抗压强度、弹性模量以及断裂韧性的尺寸效应不明显,弯曲强度则随着模型尺寸的增大而减小。建立了连续体经典断裂力学有限宽板条单边直裂纹的离散元力学模型,改变初始裂纹长度进行模拟得到的结果与单边切口梁模拟结果及文献报道的试验值一致。