Passivation of Acceptors in InP resulting from CH sub 4 /H sub 2 Reactive Ion Etching.

Reactive ion etching of InP with CH sub 4 /H sub 2 leads to hydrogen passivation of near-surface acceptors but not donors. SIMS measurements of CH sub 4 /D sub 2 etched samples show deuterium diffuses to a depth of 2000angstroms in p-InP (1. 5 x 10 sup (18) cm sup (-3) when etching at a rate of 520angstroms/min and a temperature of about 80C. Acceptor passivation occurs to the same depth. For n-InP, no donor passivation is observed, even though SIMS shows deuterium diffusion to a depth of 7000angstroms. Annealing at 350C for 1 minute restores carrier concentrations to near pre-etched levels. These data show that acceptor passivation by hydrogen in-diffusion occurs during CH sub 4 /H sub 2 reactive ion etching of InP without intentional heating, but that acceptor levels can be restored by gentle heat treatment.