KINETICS OF CHEMICAL BEAM EPITAXY FOR HIGH-QUALITY ZNS FILM GROWTH

A comprehensive study is reported of the chemical and metalorganic mol ecular beam epitaxy (CBE/MOMBE) growth of ZnS on Si and GaAs(100) subs trates for applications in advanced electroluminescent displays and fo r optoelectronic device integration on Si. Growth kinetics studies of conventional and photoassisted MOMBE and CBE using diethylzinc (DeZn) with H2S, di-isopropylsulfide (DipS) and a novel precursor, t-butyl me rcaptan (t-BuSH), are reported. The results obtained indicated that th e low temperature growth of ZnS using cracked DeZn and DipS was hinder ed. This was attributed to the reattachment of the alkyl radicals to s urface growth sites, which resulted in a lower growth rate. However, b y using uncracked DeZn and H2S or cracked DeZn and t-BuSH, this growth hindrance was removed by the surface reaction of hydrogen with the al kyl radicals. The addition of a thin CaF2 buffer layer was found to re markably improve the growth of ZnS on Si.