STUDY OF SUBSTRATE DIFFUSION IN EPITAXIAL N-TYPE CdSe FILMS GROWN ON GaAs (001) BY PULSED LASER ABLATION

N-type CdSe films with thicknesses of 470-630 nm were grown on (001) and 2"-miscut GaAs wafers by ArF (193 nm) pulsed laser ablation of stoichiometric CdSe targets at platen temperatures (Tp) of 250425°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 Tp2 355°C but was greatly reduced at Tp=250"C. Tilting the substrate to be approximately parallel to the ablation plume as well as decreasing the ambient gas pressure also reduced film-substrate interdiffusion.