Passivation of GaAs(110) with Ga2O3 thin films deposited by electron cyclotron resonance plasma reactive molecular beam epitaxy

Gallium oxide thin films deposited by electron cyclotron resonance plasma molecular beam epitaxy on GaAs(110) surfaces are reported. Room temperature photoluminescence spectra show an enhancement over as-is surfaces by greater than an order of magnitude for semi-insulating wafers. This enhancement is corroborated by low temperature photoluminescence spectra, showing a reduction in AsGa, OAs, and carbon-related emissions. The bonding configuration at the interface to GaAs was investigated by x-ray photoelectron spectroscopy depth profiling and secondary ion mass spectroscopy: Arsenic oxide related compounds were below the sensitivity limits of the former technique, while carbon (both in the film and in the vicinity of the interface) was below the sensitivity limit of the latter technique. Photoluminescence enhancement is also attributed to hydrogen passivation of EL2 defects, which is found to be stable following deposition at temperatures of 400 °C on semi-insulating and p-type wafers.