A Second-Harmonic Generation Study of GaAs-Oxide Removal Using a Hydrogen Plasma

ABSTRACTWe observed a second-harmonic generation (SHG) in reflection from a GaAs (100) surface during an oxide removal process using a pulsed hydrogen plasma. We found that the P-polarized SH intensity under P-polarized excitation decreased in the [011] azimuth of incidence and increased in the [011] azimuth of incidence during hydrogen plasma irradiation. The input polarization angle dependence of the P-polarized SH intensity before and after oxide removal was fitted to a model which includes both the surface and bulk SHG contributions. We estimated the thickness of the removed oxide based on the bulk SHG contribution change.