Thermally induced oxide crystallinity and interface destruction in Ga2O3-GaAs structures

Amorphous Ga2O3 films are deposited onto the GaAs(001) surface using effusive evaporation from a high-purity polycrystalline Ga2O3 source. The Ga2O3-GaAs structure is characterized by cross-sectional transmission electron microscopy, electron diffraction, and photoluminescence intensity measurements. As-deposited Ga2O3 films are found to be amorphous forming an atomically abrupt interface of low interface state density D-it with GaAs. For oxide films with a thickness t(ox)greater than or equal to127 Angstrom, rapid thermal annealing above a critical temperature T-c=720 degreesC induces Ga2O3 bulk crystallization resulting in structural deformation of the Ga2O3-GaAs interface and complete destruction of its low D-it character. Preliminary data suggest that the critical temperature T-c may increase in the limit of very thin Ga2O3 films. (C) 2003 American Institute of Physics.