Growth and Characterization of Thick (100) CdTe Layers on (100) GaAs and (100) GaAs/Si Substrates by Metalorganic Vapor Phase Epitaxy

The growth characteristics and the crystalline quality of thick (approximately 100 mu m) (100) CdTe epitaxial layers grown on (100) GaAs and (100) GaAs/Si substrates in a MOVPE system for X-ray, gamma-ray detectors applications were investigated. The growth rate was constant up to the layer thickness of 30 mu m, however it decreased afterwards with increasing layer thickness, which was attributed due to the decrease of the temperature at the growth surface. The FWHM values of the X-ray double crystal rocking curve decreased rapidly with increasing layers thickness, and remained around 50-70 arcsec for the layers thicker than 30 mu m on both types of substrates, indicating their high crystalline quality. However, a small amount of residual strain was still observed on these thick layers. 12 refs.