SHG(Second Harmonic Generation) in Reflection from GaAs Surfaces during Sulfur Passivation and Photochemical Washing Processes

ABSTRACTA passivation processes using Na2S and photochemical washing of GaAs (100) surfaces was studied in real time by a second-harmonic generation (SHG) technique. The intensities of surface-specific SHG signals were compared with those of photoluminescence (PL) signals. We found a remarkable similarity between the SHG and PL intensity changes during these processes. A band-bending model due to Fermi-level pinning at the surface has been applied in order to account for both the SHG and the PL intensity changes.