Dual species ion implantation in GaAs

Dual species ion implants of Se in conjunction with Ga implant in Cr-doped semi-insulating GaAs have been carried out. Electron concentration and mobility profiles have been investigated for annealed samples using differential Hall-effect and sheet-resistivity measurements. It has been shown that the dnal implantations give high maximum electron concentrations above 1 × 1019 cm−3 when those samples are annealed at 950°C using a low oxygen content CVD Si3 N4 encapsulant. Experimental results indicate that the major part of the enhanced maximum electron concentrations arise from Se donors on As vacancy sites.