GAAS SURFACE PASSIVATION USING IN-SITU OXIDE DEPOSITION

In-situ deposition of Ga2O3, SiO2, and MgO films on clean, atomically ordered (100) GaAs surfaces grown by molecular beam epitaxy using a mu ltiple-chamber ultra high vacuum system has been investigated. Using t his technique, direct bonding of oxide molecules to GaAs surface atoms revealing intrinsic oxide-GaAs interface properties has been achieved , The GaAs surface reconstruction prior to deposition as observed by r eflection high energy electron diffraction and the chemical shift of t he interfacial As 3d core level acquired by X-ray photoelectron spectr oscopy depth profiling are clearly correlated. AsxOy, or elemental As were not detectable at in-situ fabricated oxide-GaAs interfaces. In sh arp contrast to SiO2- and MgO-GaAs interfaces which are characterized by a Fermi level intrinsically pinned at midgap, Ga2O3-GaAs interfaces exhibit unique intrinsic electronic properties including an interface state density and recombination velocity in the mid 10(10) cm(-2) eV( -1) range and of 4500 cm/s, respectively.