GE SEGREGATION AND ITS SUPPRESSION IN GAAS EPILAYERS GROWN ON GE(111) SUBSTRATE

The interdiffusion of the compositional atoms was investigated at heterointerface between a GaAs epilayer and a Ge ( 1 1 1 ) substrate by secondary ion mass spectroscopy. When a thin AlAs layer is applied initially, diffusion of Ge into the GaAs epilayer was suppressed effectively. An abrupt heterointerface was successfully realized in relatively high temperature growth. The interdiffusion process at the AlAs-Ge heterointerface was clarified in high temperature growth, which was dominated by the temperature-assisted segregation of Ge atoms during the AlAs growth rather than thermal diffusion. The compositional diffusion of Al atoms into the GaAs epilayer was also observed, which was enhanced by the Ge segregation in the structure of GaAs/AlAs/Ge substrate grown at higher temperature.