In situ H2S passivation of In0.53Ga0.47As∕InP metal-oxide-semiconductor capacitors with atomic-layer deposited HfO2 gate dielectric

Abstract

We have studied an in situ passivation of ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ , based on ${\mathrm{H}}_2\mathrm{S}$ exposure $(50–350°\mathrm{C})$ following metal organic vapor phase epitaxy growth, prior to atomic layer deposition of $\mathrm{Hf}{\mathrm{O}}_2$ using $\mathrm{Hf}{\left[\mathrm{N}{\left(\mathrm{C}{\mathrm{H}}_3\right)}_2\right]}_4$ and ${\mathrm{H}}_2\mathrm{O}$ precursors. X-ray photoelectron spectroscopy revealed the suppression of As oxide formation in air exposed InGaAs surfaces for all ${\mathrm{H}}_2\mathrm{S}$ exposure temperatures. Transmission electron microscopy analysis demonstrates a reduction of the interface oxide between the ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ epitaxial layer and the amorphous $\mathrm{Hf}{\mathrm{O}}_2$ resulting from the in situ ${\mathrm{H}}_2\mathrm{S}$ passivation. The capacitance-voltage and current-voltage behavior of $\mathrm{Pd}∕\mathrm{Hf}{\mathrm{O}}_2∕{\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}∕\mathrm{In}\mathrm{P}$ structures demonstrates that the electrical characteristics of samples exposed to $50°\mathrm{C}$ ${\mathrm{H}}_2\mathrm{S}$ at the end of the metal-organic vapor-phase epitaxy ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ growth are comparable to those obtained using an ex situ aqueous ${\left(\mathrm{N}{\mathrm{H}}_4\right)}_2\mathrm{S}$ passivation.