碳化硅多型体连生现象的X射线研究

本工作用劳埃法对分布于三十二炉的四百多个碳化硅单晶进行了类型分布、连生规律和结构完整性等的分析。大量的观察表明,碳化硅片状晶体中的共轴平行连生是一种普遍的现象,二种以上类型的连生占晶体总数的三分之二。文中列出了各种连生类型的统计。系统地报导了SiC晶体连生状况的X射线法实验结果。对各炉晶体所作的类型分布的分析表明,不同的制备条件下影响较大的是颜色和结构完整度。类型分布的规律性并不明显,邻近的晶体类型可以完全相异。用实验数据分析了类型、颜色和蚀坑间的关系。对碳化硅多型体产生的机理作了讨论。

X-RAY STUDIES ON SYNTAXIC COALESCENCE PHENOMENON OF POLYTYPES IN SiC

By means of the Laue X-ray diffraction method the distribution of polytypes, rule and characteristic features of syntaxic coalescence, and crystal perfection of 400 silicon carbide single crystals, which were taken from graphite furnace and induction furnace of 32 experimental runs and from industrial furnace, have been studied. Numerous observations demonstrate that parallel coalescence in plate silicon carbide single crystal is a very common phenomenon. The crystals with coalescence of more than two polytypes amount to about 2/3 of the crystals studied, whereas crystals of the single type amount to only 1/3. Sometimes coalescence consists of even above 4-5 polytypes.The analysis of polytype distribution in furnace indicates that the polytypes are distributed irregularly, and different polytypes may be found even at the same place of one furnace. The relations among polytype, colour, and etching figure in SiC are analysed. Finally, the different mechanisms of polytype formation in silicon carbide suggested up to date are discussed.