Effect of an in situ hydrogen plasma pre-treatment on the reduction of GaSb native oxides prior to atomic layer deposition

The influence of an in situ hydrogen plasma pre-treatment on the modification of native oxides of GaSb surfaces prior to atomic layer deposition (ALD) is presented. The effects of varying rf-plasma power, exposure time, and substrate temperature have been characterized by atomic force microscopy (AFM), ex situ X-ray photoelectron spectroscopy (XPS), as well as capacitance–voltage (C–V) measurements on fabricated devices. Results indicate that a completely oxide free surface may not be necessary to produce a good electrical interface with a subsequent ALD Al2O3 dielectric; the most effective hydrogen plasma treatments resulted in the absence of Sb-oxides, a reduction in elemental Sb, and an increase in the Ga2O3 content at the interface. The use of an in situ hydrogen plasma pre-treatment eliminates the need for wet chemical etches and may also be relevant to the deposition of other high-k dielectrics, making it a promising technique for realizing high performance Sb-based MOS-devices.