Study of Substrate Diffusion in Epitaxial N-type CdSe Films Grown on GaAs (001) by Pulsed Laser Ablation

摘要

N-type CdSe films with thickensses of 470 - 630 nm were grown on (001) and 2 deg - miscut GaAs wafers by ArF (193 nm) pulsed laser ablation of stoichiometric CdSe targets at platen temperatures (T_p) of 250 - 425 deg C in vacuum and ambient Ar gas. Film-substrate interdiffusion was studied with Auger depth profiling, as well as energy dispersive x-ray fluorescent spectroscopy (EDS). Both techniques showed that extensive interdiffusion took place at the film-substrate interface for CdSe films grown at T_p>=355 deg C but was greatly reduced at T_p=250 deg C. Tilting the substrate to be approximately aprallel to the ablation plume as well as decreasing the ambient gas pressure also reduced film-substrate interdiffusion.