BACK SURFACE GETTERING AND CR OUT-DIFFUSION IN VPE GAAS-LAYERS

Mechanical back surface damage gettering has been investigated for improving the quality of GaAs substrates and VPE layers on semi-insulating GaAs. It has been shown that the pregettering of substrates reduces the interfacial defect density and alters the level of Cr out-diffusion into the VPE layer during growth. At a postdeposition anneal temperature of 800°C, Cr out-diffusion into the VPE layer is relatively suppressed in the pregettered substrate, while the ungettered sample shows larger concentrations of Cr within the epitaxial layer.