ABSTRACT
Electrical characteristics, such as the movable range of surface Fermi level (EF ) and the interface-state density (Nss ) of dielectrics/GaAs interfaces, are characterized by electroreflectance technique. A particular focus of the this work is on the recent refinement in our diagnostic scheme, whose enhanced accuracy reveals an overall picture for dielectric film/GaAs interface characteristics. It is found that the Nss is U-shaped with its minimum at the midgap (Ec -0.72eV) and the movable range of surface-EF is strongly limited within this U due to a large density of interface charges. We have also observed the reduction of Nss due to surface treatment prior to the deposition of dielectric film.
