We present the materials growth and properties of both epitaxial and amorphous films of Gd2O3 (κ=14) and Y2O3 (κ=18) as the alternative gate dielectrics for Si. The rare earth oxide films were prepared by ultrahigh vacuum vapor deposition from an oxide source. The use of vicinal Si (100) substrates is key to the growth of (110) oriented, single domain films in the Mn2O3 structure. Compared to SiO2 gate oxide, the crystalline Gd2O3 and Y2O3 oxide films show a reduction of electrical leakage at 1 V by four orders of magnitude over an equivalent oxide thickness range of 10–20 Å. The leakage of amorphous Y2O3 films is about six orders of magnitude better than SiO2 due to a smooth morphology and abrupt interface with Si. The absence of SiO2 segregation at the dielectric/Si interface is established from infrared absorption spectroscopy and scanning transmission electron microscopy. The amorphous Gd2O3 and Y2O3 films withstand the high temperature anneals to 850 °C and remain electrically and chemically intact.

We report magnetotransport measurements in a wide quantum well as the electron charge distribution is tuned from a single-layer through an interacting bilayer configuration to weakly coupled parallel layers. The system exhibits a remarkably rich set of correlated bilayer states including unique fractional quantum Hall states at even-denominator fillings and insulating phases which are consistent with pinned, bilayer Wigner crystal states.

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Atomic-layer-deposited high dielectric HfO 2 films on air-exposed In 0.53 Ga 0.47 As/ InP ͑100͒, using Hf͑NCH 3 C 2 H 5 ͒ 4 and H 2 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 ͑XPS͒ with synchrotron radiation, however, observed the existence of Ga 2 O 3 , In 2 O 3 , and In͑OH͒ 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 ϳ10 −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 2 ϫ 10 12 cm −2 eV −1 was derived. A conduction-band offset of 1.8Ϯ 0.1 eV and a valence-band offset of 2.9Ϯ 0.1 eV have been determined using the current transport data and XPS, respectively.