G. Patriarche et al., IMPERFECTIONS IN II-VI SEMICONDUCTOR LAYERS EPITAXIALLY GROWN BY ORGANOMETALLIC CHEMICAL VAPOR-DEPOSITION ON GAAS, Journal of crystal growth, 129(3-4), 1993, pp. 375-384
II-VI semiconductor heteroepitaxial layers have been grown on (001) Ga
As substrates by OMCVD, at temperatures of 365-degrees-C. The systems
were CdTe/ZnTe/GaAs, where, in some cases, (CdHg)Te was grown on top o
f CdTe. We have examined the interfaces by transmission electron micro
scopy (TEM). The ZnTe/GaAs interface is abrupt and contains misfit dis
locations. On the contrary, there is no TEM contrast at the ZnTe/CdTe
interface. Threading dislocations can also be observed (CdHg)Te grown
on top of CdTe contains a remarkably low dislocation density. This is
due to the interdiffusion multilayer process used for their preparatio
n, which consists to, first, deposit alternate HgTe/CdTe layers (misfi
t approximately 0.3%). This initial strained superlattice eliminates d
islocations. X-ray microanalysis and secondary ion mass spectrometry h
ave been used to detect the presence of impurities in the layers. Arse
nic and gallium were found in concentrations up to a few percent in II
-VI semiconductors. Their presence is due to interdiffusion in the lat
tice and along dislocations.