氢气氛区熔硅单晶热处理缺陷形成机理

本文用X射线衍射形貌法、红外吸收光谱法和金相腐蚀坑法,探讨了氢气氛区熔硅单晶热处理缺陷的形成机理。在生长态晶体中存在着三种Si-H键,对应的红外吸收峰波长分别为4.55微米、4.75微米和5.13微米。随着加热过程的进行,Si—H键逐渐分解而消失。5.13微米吸收峰的消失温度是450℃,4.55微米吸收峰的消失温度是600℃,4.75微米吸收峰的消失温度是700℃。晶体中的热处理缺陷是由于氢沉淀造成的,沉淀过程首先是Si—H键分解,然后是氢的扩散和聚集。沉淀过程的激活能是2.4电子伏特(56000卡/克分关键词：

MECHANISM OF THE FORMATION OF THE DEFECTS DURING HEAT TREATMENT IN SINGLE SILICON CRYSTAL GROWN BY FLOATING ZONE METHOD UNDER PURE HYDROGEN

The mechanism of the formation of the defects during heat treatment in single silicon crystal, which had been grown by floating zone method under pure hydrogen, have been studied by means of X-ray topography, infrared absorption spectrography and chemical etching method.Three kinds of Si-H bonds were observed in the as-grown crystal, their infrared absorption peaks were at 4.55 μm, 4.75 μm and 5.13μm respectively. During heating these Si-H bonds were broken up gradually and dis appeared at last. The disappearing temperature of 5.1μm, 4.55 μm, and 4.75 μm absorption peaks were 450℃, 600℃ and 700℃ respectively.The heat-treatment defects were originated from hydrogen precipitation in the crystal. The sequence of the precipitation process was found to be as follows: Si-H bonds were broken at first, and then hydrogen diffused and coalesced together. The activitation energy of the precipitation process was found to be 2.4 eV (56000 cal/mol).Due to hydrogen preciptation, the prismatic dislocation loops were formed around hydrogen precipitates at definite temperature (about 600-700℃).