PASSIVATION OF THE INP SURFACE USING POLYSULFIDE AND SILICON-NITRIDE OVERLAYER

For the first time, excellent passivation of the defect states at the SiN(x)/InP interface has been achieved using ammonium sulfide solution containing excess sulfur and phosphorous pentasulfide. Silicon nitride overlayers have been deposited at approximately 200-degrees-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 approximately 10(12) cm-2 eV-1. The devices are stable, with no noticeable change observed over a 30-day period.