Zirconium silicate (ZrSixOy) gate dielectric films with ˜3-5 at. % Zr exhibit excellent electrical properties and high thermal stability in direct contact with Si. We demonstrate an equivalent oxide thickness of about 21 Å for a 50 Å ZrSixOy film sputter-deposited directly on a Si substrate, as measured by capacitance-voltage techniques, with a hysteresis shift less than 10 mV. Leakage currents for these films are very low, approximately 1×10-6 A/cm2 at 1.0 V bias in accumulation. Films ramped to hard breakdown exhibit breakdown fields Ebd ˜10 MV/cm. Excellent electrical properties are obtained with Au electrodes, in particular.