Passivation of the InP surface using polysulfide and silicon nitride overlayer

Abstract

For the first time, excellent passivation of the defect states at the SiNx/InP interface has been achieved using ammonium sulfide solution containing excess sulfur and phosphorous pentasulfide. Silicon nitride overlayers have been deposited at ∼200 °C using electron cyclotron resonance plasma-enhanced chemical vapor deposition technique. The room-temperature integrated photoluminescence (PL) intensity of the passivated InP approximately doubled following the nitride deposition. Under similar conditions, the PL intensity of the untreated sample decreased by a factor of five. The interface trap density, estimated using the high-low capacitance technique, is ∼1012 cm−2 eV−1. The devices are stable, with no noticeable change observed over a 30-day period.