COMMON ANION RULE IN COMPOUND SEMICONDUCTOR MIS SYSTEMS.

Density distribution and photoionization properties of interface states in GaAs, InP, GaP and InGaAs metal-insulator-semiconductor (MIS) interfaces are investigated on the basis of C-V and photocapacitance transient spectroscopy (PCTS) measaurement. U-shaped distributions without any characteristic peaks were observed. Energy location for minimum state density was found to be a characteristic point for each semiconductor. It was found that this location agrees within plus or minus 0. 1 ev with the Fermi level pinning position at the metal-semiconductor interfaces, which is known to obey empirically the common anion rule. It is also found that the photon energy dependence of the photoionization cross-section is similar for Si, GaAs, InP and InGaAs. The unified defect cannot explain these experimental results. A surface disorder model is shown to be capable of explaining the experimental observation.