非晶硅薄膜的低温快速晶化及其结构分析

在镀铝的廉价玻璃衬底上高速沉积的非晶硅薄膜在不同的温度下退火10min.退火温度为500℃时,薄膜表面形成了硅铝的混合相,非晶硅薄膜开始呈现了晶化现象 退火温度为550℃时,大部分(约80%)的非晶硅晶化为多晶硅,平均晶粒尺寸为500nm 退火温度为600℃时,几乎所有的非晶硅都转化为多晶硅,其平均晶粒尺寸约为15μm.     

Low-Temperature Growth of Polycrystalline silicon Films by SiCl4／H2 rf Plasma Enhanced Chemical Vapour Deposition

Polycrystalline silicon film was directly fabricated at 200℃ by the conventional plasma enhanced chemical vapour deposition method from SiCl4 with H2 dilution. The crystallization depends strongly on the deposition power.The maximum crystMlinity and the crystalline grain size are over 80% and 200—50Onm, respectively. The results of energy dispersive spectroscopy and infrared spectroscopy measurements demonstrate that the film is mostly composed of silicon, without impurities such as Cl, N, C and bonded H. It is suggested that the crystallization at such a low temperature originates from the effects of chlorine, i.e., in-situ chemical, etching, in-situ chemical cleaning, and the detachment of bonded H.     

基片光学特性对薄膜光强透过谱的影响

在考虑基片与空气界面反射率以及基片吸收不能忽略的情况下，对常见的基片上薄膜的光强透过率公式进行了修正，导出了该情况下的透过率公式．以非晶硅薄膜为研究对象，采用模拟计算说明基片光学特性对薄膜光强透过谱的影响．     

用SiCl4-H2低温沉积多晶硅薄膜微结构的Raman分析

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A Movable Mass Spectroscopy Sampling Apparatus for Measuring Spatial Distribution of Neutral Radicals in Silane Plasma

A movable mass spectroscopy gas sampling apparatus has been established and a straight-line fit of silane depletion fraction f is proposed. The spatial density distributions of SiHn (n=0-3) radicals in silane radio frequency glow discharge have been measured by a mass spectrometer. The experimental results demonstrate that the densities of the neutral radicals have the peak value near the middle position of electrodes, and the densities of SiH2 and SiH3 are higher than those of Si and SiH in silane plasma. This reveals that SiH2 and SiH3 may be the primary precursors in forming the a-Si:H film.     

AlGaN/GaN高电子迁移率器件外部边缘电容的物理模型

AlGaN/GaN HEMT外部边缘电容Cofd是由栅极垂直侧壁与二维电子气水平壁之间的电场构成的等效电容.本文基于保角映射法对Cofd进行物理建模,考虑沟道长度调制效应,研究外部偏置、阈值电压漂移和温度变化对Cofd的影响:随着漏源偏压从零开始增加,Cofd先保持不变再开始衰减,其衰减速率随栅源偏压的增加而减缓;AlGaN势垒层中施主杂质浓度的减小和Al组分的减小都可引起阈值电压的正向漂移,正向阈值漂移会加强沟道长度调制效应对Cofd的影响,导致Cofd呈线性衰减.在大漏极偏压工作情况下,Cofd对器件工作温度的变化更加敏感.     

一个开关电源实验

介绍一个供学生用的实验用开关稳压电路。用以观察、研究稳压电源的性能与振荡频率之关系     

射频辉光放电等离子体的电探针诊断及数据处理

Langmuir探针是等离子体诊断的一个重要方法.对探针I-V曲线进行求解二次微商是获得等离子体中的电子能量分布函数的关键.由Fourier变换导出一个求解微商的数值解方法.克服了现有方法所存在的缺点.实现了对探针I-V曲线求解二次微商的精确、自动运算.测量了硅烷射频辉光放电等离子体的平均电子能量(温度)和浓度随放电功率的变化. 关键词：     

倒装芯片塑料球栅阵列封装器件在外应力下的失效机理

倒装芯片塑料球栅阵列(FC-PBGA)封装形式独特而被广泛应用, 分析研究其在实际应用过程中, 在高温、电、水汽等多种综合环境应力条件作用下的失效机理对提高其应用可靠性有重要意义. 本文对0.13 μm 6层铜布线工艺的FC-PBGA FPGA器件, 通过暴露器件在以高温回流焊过程中的热-机械应力为主的综合外应力作用下的失效模式, 分析与失效模式相对应的失效机理. 研究结果表明, FC-PBGA器件组装时的内外温差及高温回流焊安装过程中所产生的热-机械应力是导致失效的根本原因, 在该应力作用下, 芯片上的焊球会发生再熔融、桥接相邻焊球致器件短路失效; 芯片与基板之间的填充料会发生裂缝分层、倒装芯片焊球开裂/脱落致器件开路失效; 芯片内部的铜/低k互连结构的完整性受损伤而影响FC-PBGA器件的使用寿命.     

The reliability of measurements on electron energy distribution function in silane rf glow discharges

Electron energy distribution function (EEDF) is a key parameter of plasmas, which is directly proportional to the second derivative of the probe I-V characteristics. Because of an amplifying effect of unavoidable noises in the experimental probe I-V curves during the derivation process, the experimental I-V curves should be smoothed before performing the numerical derivation. This paper investigates the effect of adjustable factors used in the smoothing process on the deduced second derivative of the I-V curves, and an optimum group of the adjustable factors is selected to make the rms deviation of the smoothed I-V curves from the measured curves less than 1%. A simple differentiation circuit is designed and used to measure the EEDF parameter straightforwardly. It is the first time, so far as we know, to measure the EEDF parameters simultaneously by means of both numerical and circuit derivative methods under the same discharge conditions and on the same discharge equipment. The deviation between two groups of mean electron energy E and electron density n_e obtained by the above different methods is within about 7%. This apparently improves the reliability of the measurements of the EEDF parameters.