Fabrication of metal-oxide-semiconductor field-effect transistors using crystalline γ-Al2O3 films as the gate dielectrics

Crystalline gamma-Al2O3 films were employed as high-kappa gate dielectrics in metal-oxide-semiconductor field-effect transistors (MOSFETs) and characterization of these devices was performed. The crystalline dielectric was deposited with thicknesses of 4.0-4.5 nm by mixed source molecular beam epitaxy and the capacitance equivalent thicknesses obtained were 2.7-2.9 nm. The MOSFETs had exceptionally steep subthreshold slopes (63-67 mV/decade), relatively low negative fixed charge densities (5-7x10(12) cm(-2)) and interface state densities (2-3x10(11) eV(-1) cm(-2)). The maximum values of the effective carrier mobilities were 145 cm(2)/V s for electrons and 85 cm(2)/V s for holes. (C) 2004 American Institute of Physics.