Ohmic contacts on ion-implanted n-type GaAs layers

Abstract
Contact resistance of Ohmic electrodes formed on either Se- or (Se+Ga) -implanted n-type GaAs layers was studied. Experimental results have shown that a low specific-contact resistance of 2.9×10−7 Ω cm2 can be achieved on GaAs layers having a maximum carrier concentration of 1.8×1019 cm−3, which have been formed by a dual-species (4.4×1014 cm−2 Se+ 5.0×1014 cm−2 Ga) implantation in Cr-doped semi-insulating GaAs heated to 400 °C and by subsequent annealing at 950 °C using an oxygen-free CVD Si3N4 layer as an encapsulant.