Monolayer surface doping of GaAs from a plated zinc source

We have investigated surface doping and diffusion of Zn in GaAs using rapid thermal processing. The use of an aqueous RuCl3 pretreatment has enabled us to electroplate uniform ≊100-Å-thick Zn layers directly on the GaAs surface. The excess Zn is removed with a 500 °C vacuum ‘‘evaporation,’’ leaving a modified surface layer which may serve as a dopant source for rapid thermal diffusion. Evaporation of A1 onto such surfaces yields Schottky diodes with enhanced barrier heights which have been used to fabricate metal-semiconductor field-effect transistor structures.