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采用新设计的电极结构的等离子体增强化学气相沉积 (PECVD)技术 ,在高功率密度、高氢稀释比、低温、偏压及低反应气压的条件下 ,在衬底表面形成双等离子流 ,增加了衬底表面SiC的成核概率 ,增强成核作用 ,形成纳米晶 .采用高H2 等离子体刻蚀弱的、扭曲的、非晶Si—C及Si—Si和Si—H等键时 ,由于H等离子体对纳米SiC晶粒与非晶态键的差异刻蚀作用 ,产生自组织生长 ,发生晶化 .Raman光谱和透射电子衍射 (TEM)的测试结果表明 ,纳米晶SiC是 4H SiC多型结构 .电子显微照片表明平均粒径为 16nm ,形状为微柱体 .实验结果指出 ,SiC纳米晶的形成必须经过偏压预处理成核 ,并且其晶化存在一个功率密度阈值 ;当低于这一功率密度阈值时 ,晶化消失 ;当超过这一阈值时 ,纳米晶含量随功率密度的提高而增加 .随着晶化作用的加强 ,电导率增加 .
The plasma enhanced chemical vapor deposition (PECVD) technology of a newly designed electrode structure is used to form a double plasma flow on the surface of a substrate under high power density, high hydrogen dilution ratio, low temperature, bias voltage and low reaction pressure, The probability of nucleation of SiC on the surface of the substrate is increased and nucleation is enhanced to form nanocrystals. When high H2 plasma is used to etch weak, distorted, amorphous Si-C and Si-Si and Si-H bonds, H plasma on the nano-SiC grain and amorphous bond of the differential etching, resulting in self-growth, crystallization occurred.Raman spectroscopy and transmission electron diffraction (TEM) test results show that the nano-SiC SiC 4H polytype Structure.The electron micrograph shows that the average particle size is 16nm and the shape is a micropillars.The experimental results show that the formation of SiC nanocrystals must be pre-treated by bias pretreatment and have a power density threshold for crystallization. When this power density threshold is reached, the crystallization disappears, and when it exceeds this threshold, the nanocrystalline content increases with increasing power density, and as the crystallization proceeds, the conductivity increases.