AES and SRUPS studies on surface passivation of GaAs by (NH4)2Sx sulfurization techniques

The surface passivation technique using (NH4)2Sx on GaAs(100) surface was investigated. With this surface treatment, the effective barrier heights for both AlGaAs and AuGaAs Schottky diodes were found to vary with the metal work functions, which is clear evidence of the lower surface state density. AES and SRUPS measurements were done to characterize the surfaces including their compositions. In this paper, interpretations on this novel passivation effect are also provided.