Dislocation cell structures in CdZnTe substrates and its behavior of threading into HgCdTe LPE epilayers

摘要

Dislocation cell structures in CdZnTe substrates and its behavior of threading into HgCdTe LPE epilayers were studied. A kind of dislocation cell structure of which dislocations linearly pile up to three <1 1 0> orientations on the (1 1 1)B face of CdZnTe crystal was found. The formation of this cell structure can be demonstrated by the enrichment of the dislocations through slip during the growth or cooling process. By comparing the dislocation densities and distributions of HgCdTe LPE epilayers with it of CdZnTe substrates at the constant region using an optical microscopy system, the behavior of cell structures of CdZnTe substrates threading into HgCdTe LPE epilayers were also discussed. The results show that the stored dislocation densities at the dislocation walls can significantly affect the behavior of dislocation cell structures threading into HgCdTe LPE epilayers. Dislocation cell structures of which dislocation walls have higher stored dislocation densities can appear in constant region of HgCdTe epilayers. But the dislocations of HgCdTe epilayers growth on CdZnTe substrate with lower stored dislocation densities at the dislocation walls are almost uniformly distributed.