We report on high effective mobilities in yttrium-oxide-based n-channel met
al-oxide-semiconductor field-effect transistors (MOSFETs) with aluminum gat
es. The yttrium oxide was grown in ultrahigh vacuum using a reactive atomic
-beam-deposition system. Medium-energy ion-scattering studies indicate an o
xide with an approximate composition of Y2O3 on top of a thin layer of inte
rfacial SiO2. The thickness of this interfacial oxide as well as the effect
ive mobility are found to be dependent on the postgrowth anneal conditions.
Optimum conditions result in mobilities approaching that of SiO2-based MOS
FETs at higher fields with peak mobilities at approximately 210 cm(2)/V s.
(C) 2001 American Institute of Physics.