Sulfur Passivation of InP and GaAs

Abstract

ABSTRACTPassivation of electronic defect states at the SiNx/InP and the SiNx/GaAs interfaces has been achieved using both ‘wet’ (ammonium and phosphorous polysulfide solutions) and ‘dry’ (H2S gas) sulfur treatments. The passivated surfaces are encapsulated by depositing SiNx overlayers at ∼ 200 °C using the electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD) technique. The capacitance-voltage (C-V) characteristics of metal-insulatorsemiconductor (MIS) capacitors indicate substantial reduction in the density of interface defects. Schottky diodes, fabricated in sulfur-treated n-GaAs, also exhibit significant improvements. The H2S-treatment provides better reproducibility and uniformity when compared with the ‘wet’ sulfide treatment of the surfaces.