Fabrication of metal-oxide-semiconductor field-effect transistors using crystalline γ-Al_(2)O_(3) films as the gate dielectrics

摘要

Crystalline γ-Al_(2)O_(3) films were employed as high-κ 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 (5-7×10~(12) cm~(-2)) and interface state densities (2-3×10~(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.