In situ H₂S passivation of In_0.53Ga _0.47As/InP metal-oxide-semiconductor capacitors with atomic-layer deposited HfO₂ gate dielectric

We have studied an in situ passivation of In0.53 Ga0.47 As, based on H2 S exposure (50-350 °C) following metal organic vapor phase epitaxy growth, prior to atomic layer deposition of Hf O2 using Hf [N (C H3)2] 4 and H2 O precursors. X-ray photoelectron spectroscopy revealed the suppression of As oxide formation in air exposed InGaAs surfaces for all H2 S exposure temperatures. Transmission electron microscopy analysis demonstrates a reduction of the interface oxide between the In0.53 Ga0.47 As epitaxial layer and the amorphous Hf O2 resulting from the in situ H2 S passivation. The capacitance-voltage and current-voltage behavior of PdHf O2 In0.53 Ga0.47 AsInP structures demonstrates that the electrical characteristics of samples exposed to 50 °C H2 S at the end of the metal-organic vapor-phase epitaxy In0.53 Ga0.47 As growth are comparable to those obtained using an ex situ aqueous (N H4)2 S passivation.