Hard X-ray photo-electron spectroscopy was performed on In0.53Ga0.47As/Al2O3 gate stacks as deposited and annealed at 400, 500 and 700C to test for out-diffusion of substrate elements. The Ga and As core-level intensities increased with increasing anneal temperature, while the In intensity decreases. Hard X-ray photo-electron spectroscopy was performed at two different beam energies to vary the surface sensitivity; results demonstrated that Ga and As out-diffused into the Al2O3 film. Analysis suggested the presence of an interlayer containing Ga and As oxides, which thickens with increasing anneal temperature. Further diffusion, especially of Ga, into the Al2O3 film was also observed with increasing anneal temperature.

Hard X-Ray Photoelectron Spectroscopy Study of As and Ga Out-Diffusion in In0.53Ga0.47As/Al2O3 Film Systems. C.Weiland, P.Lysaght, J.Price, J.Huang, J.C.Woicik: Applied Physics Letters, 2012, 101[6], 061602