Y2O3, as a common high κ gate dielectric, has been directly deposited on (In)GaAs, GaSb, and Ge using electron beam evaporation in ultra-high vacuum. These semiconductors have distinctly different chemical bonding and surface electronic characteristics. No interfacial passivation layer was employed. High-quality Y2O3/semiconductor interfaces have been achieved, resulting in low interfacial trap densities and high-temperature thermal stability, essential for the CMOS compatible process. Self-aligned inversion channel n-InGaAs, p-GaSb, and p-Ge MOSFETs have been fabricated with excellent device performances.