Detection of Ga suboxides and their impact on III-V passivation and Fermi-level pinning

The passivation of interface states remains an important problem for III-V based semiconductor devices. The role of the most stable bound native oxides GaO(x) (0.5 <= x <= 1.5) is of particular interest. Using monochromatic x-ray photoelectron spectroscopy in conjunction with controlled GaAs(100) and InGaAs(100) surfaces, a stable suboxide (Ga(2)O) bond is detected at the interface but does not appear to be detrimental to device characteristics. In contrast, the removal of the Ga 3+ oxidation state (Ga(2)O(3)) is shown to result in the reduction of frequency dispersion in capacitors and greatly improved performance in III-V based devices.