Passivation of acceptors in InP resulting from CH4/H2 reactive ion etching

Abstract

Reactive ion etching of InP with CH4/H2 mixtures leads to hydrogen passivation of near-surface Zn acceptors but not S donors. Secondary-ion mass spectrometry (SIMS) measurements of CH4/D2 etched samples show deuterium diffuses to a depth of 2000 Å in p-InP (1.5×1018 cm−3) when etching at a rate of 520 Å/min and a temperature of about 80 °C. 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 7000 Å. Annealing at 350 °C for 1 min restores carrier concentrations to near pre-etched levels.