Atomic-layer-deposited HfO2 on In0.53Ga0.47As: Passivation and energy-band parameters

Abstract

Atomic-layer-deposited high $\kappa$ dielectric $\mathrm{Hf}{\mathrm{O}}_2$ films on air-exposed ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}∕\mathrm{In}\mathrm{P}$ (100), using $\mathrm{Hf}{\left(\mathrm{N}\mathrm{C}{\mathrm{H}}_3{\mathrm{C}}_2{\mathrm{H}}_5\right)}_4$ and ${\mathrm{H}}_2\mathrm{O}$ as the precursors, were found to have an atomically sharp interface free of arsenic oxides, an important aspect for Fermi level unpinning. A careful and thorough probing, using high-resolution angular-resolved x-ray photoelectron spectroscopy (XPS) with synchrotron radiation, however, observed the existence of ${\mathrm{Ga}}_2{\mathrm{O}}_3$ , ${\mathrm{In}}_2{\mathrm{O}}_3$ , and $\mathrm{In}{\left(\mathrm{O}\mathrm{H}\right)}_3$ at the interface. The current transport of the metal-oxide-semiconductor capacitor for an oxide $7.8\mathrm{nm}$ thick follows the Fowler–Nordheim tunneling mechanism and shows a low leakage current density of $\sim {10}^{-8}\mathrm{A}∕{\mathrm{cm}}^2$ at $V_{\mathrm{FB}}+1\mathrm{V}$ . Well behaved frequency-varying capacitance-voltage curves were measured and an interfacial density of states of $2\times {10}^{12}{\mathrm{cm}}^{-2}{\mathrm{eV}}^{-1}$ was derived. A conduction-band offset of $1.8\pm 0.1\mathrm{eV}$ and a valence-band offset of $2.9\pm 0.1\mathrm{eV}$ have been determined using the current transport data and XPS, respectively.