Diffusion of Si in GaAs From a Thin Si Film by Pulsed Laser Irradiation

Abstract

ABSTRACTThe diffusion of Si into GaAs from a thin source has been investigated. Electron beam evaporated Si films were deposited on chromium–doped GaAs wafers. Pulsed irradiation from a Q–switched Nd:YAG laser resulted in the formation of n+ layers. After metal evaporation these layers displayed nonalloyed ohmic contact behavior of very low contact resistance (5×10−7 Ω−cm2 ) and good thermal stability at 300°C. SIMS analysis of these layers revealed a steplike Si profile and significant chromium redistribution within the laser induced molten layer. A major improvement in surface morphology was obtained using Si02 encapsulants.