摘要
<p>Atomic-layer-deposited high κ dielectric HfO<sub>2</sub> films on air-exposed In<sub>0.53</sub>Ga<sub>0.47</sub>As/InP (100)<font face="Calibri, sans-serif"><span style="font-size: 16px;"><i>, </i></span></font>using Hf(NCH<sub>3</sub>C<sub>2</sub>H<sub>5</sub>)<sub>4</sub> and H<sub>2</sub>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 Ga<sub>2</sub>O<sub>3</sub>, In<sub>2</sub>O<sub>3</sub>, and In(OH)<sub>3</sub> 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<sup>−8</sup> A/cm<sup>2</sup> at V<sub>FB</sub>+1 V. Well behaved frequency-varying capacitance-voltage curves were measured and an interfacial density of states of 2x10<sup>12</sup> cm<sup>−2</sup> eV<sup>−1</sup> was derived. A conduction-band offset of 1.8<span style="font-size:12.0pt"><span style="font-family:"新細明體","serif"">±</span></span>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.</p>