Crystal microstructure of PbTe/Si and PbTe/SiO_2/Si thin films

摘要

A modified 'hot wall' technique (HWE) is used for growth of PbTe thin films directly on Si(100) high ohmic substrates both with and without any buffer layers. The previously formed SiO_2 films have been used as buffer layers. The crystal microstructure of PbTe thin films has been studied by an etching pits method, SEM, RHEED and by X-ray analysis which is able to determine the X-ray rocking curve profiles and line width with high precision.. It has been found that these PbTe/Si and PbTe/SiO_2/Si thin films have mosaic single crystal structure with (100) texture without regard to the Si substrate orientation. The investigations of PbTe/Si thin films dislocation density by the etching pits method and by the analysis of X-ray reflection profiles show the average values of about 10~5-10~7 cm~(-2). The experimental results of these methods have shown that PbTe/SiO_2/Si thin films had better crystallinity perfection. The average values of dislocation density were about 5X10~4-2X10~5 cm~(-2).