多层HgCdTe异质外延材料的热退火应力分析

Stress effects on multi-heterostructure HgCdTe by thermal annealing

前期研究采用高温热处理方法,获得了抑制位错的最佳退火条件.通过比对实验,发现不同衬底上HgCdTe表面的CdTe钝化层在热处理过程中对位错的抑制作用各有不同.结合晶格失配应力和热应力对不同异质结构进行理论计算,借助X射线摇摆曲线的倒易空间分析,解释了CdTe钝化层对HgCdTe位错抑制的影响作用.

With the rapid development in larger-area HgCdTe infrared detector device, high-quality HgCdTe epilayers grown by molecular beam epitaxy （MBE） are required. One of its challenges is to reduce the high dislocation density in HgCdTe. In this paper, thermal annealing （TA） had been performed and the best annealing temperature and time have been acquired. A series of researches were performed to study the effects of the CdTe passivation layer over HgCdTe on dislocation reduction after thermal annealing. The relation of lattice mismatch stress and thermal stress in HgCdTe layer in the TA process was studied by theoretical calculation. Reciprocal space of X-ray rocking curve of HgCdTe was also analyzed. It explained the different phenomena of HgCdTe epilayer with and without CdTe cap in the TA process.