Photoluminescence characterization of air exposed AlGaAs surface and passivated ex situ by ultrathin silicon interface control layer

Abstract Using the photoluminescence surface state spectroscopy (PLS 3 ) technique, attempts were made to determine the surface state density ( N ss ) distribution on Al x Ga 1− x As ( x ≈0.3) surfaces passivated by the Si interface control layer (ICL) technique. Air-exposed AlGaAs epitaxial wafers which are technologically important for fabrication of various devices were passivated ex situ by forming a SiO 2 /Si 3 N 4 /Si ICL/AlGaAs structure after the HCl treatment and their photoluminescence behavior was investigated in detail. The result of the PLS 3 analysis indicated that Si ICL-based passivation reduces the minimum interface state density value down to 10 10  cm −2  eV −1 range. Some indication was also obtained that further improvements are possible by using electron cyclotron resonance (ECR)-enhanced N 2 plasma for Si 3 N 4 /Si ICL interface formation.