Electronic properties of atomic-layer-deposited high-k dielectrics on GaSb(001) with hydrogen plasma pretreatment

In this report, the authors investigate the use of H2/Ar-plasma exposure as a means for achieving high-quality electrical interfaces between p-type GaSb and atomic-layer-deposited Al2O3 dielectric films. Dry in-situ plasma treatments are shown to reduce the estimated density of interface states by over two orders of magnitude compared to a standard wet HCl-treatment, without increasing gate leakage. The chemical compositions of the natively oxidized and treated GaSb surfaces are analyzed via x-ray photoemission spectroscopy (XPS). XPS spectra indicate that the native GaSb oxide is segregated, with Sb-oxide compounds localized at the air interface. Effective H2/Ar-plasma treatments act to remove the Sb-oxide, resulting in a surface Ga-oxide layer enriched in Ga2O3.