Abstract
Atomic-layer-deposited high κ dielectric Hf O2 films on air-exposed In0.53 Ga0.47 AsInP (100), using Hf (NC H3 C2 H5)4 and H2 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 Ga2 O3, In2 O3, 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 ∼ 10-8 A cm2 at VFB +1 V. Well behaved frequency-varying capacitance-voltage curves were measured and an interfacial density of states of 2× 1012 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. © 2008 American Institute of Physics.