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

Atomic-layer-deposited high kappa dielectric HfO2 films on air-exposed In0.53Ga0.47As/InP (100), using Hf(NCH3C2H5)(4) and H2O 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 Ga2O3, In2O3, and In(OH)(3) at the interface. The current transport of the metal-oxide-semiconductor capacitor for an oxide 7.8 nm thick follows the Fowler-Nordheim tunneling mechanism and shows a low leakage current density of similar to 10(-8) A/cm(2) at V-FB+1 V. Well behaved frequency-varying capacitance-voltage curves were measured and an interfacial density of states of 2x10(12) cm(-2) eV(-1) was derived. A conduction-band offset of 1.8 +/- 0.1 eV and a valence-band offset of 2.9 +/- 0.1 eV have been determined using the current transport data and XPS, respectively. (C) 2008 American Institute of Physics.