We have developed a high-quality gate oxide on Si0.6Ge0.4 with a 30 Angstrom Si top layer. The good oxide integrity comparable to conventional thermal oxide is demonstrated by the low interface trap density of 6.2 X 10(10) eV(-1) cm(-2), low bride charge of 5.8 X 10(10) cm(-2), small leakage current at 3.3 V of 4.2 x 10(-8) A/cm(2), high breakdown field of 13.8 MV/cm, good charge-to-breakdown of 5.2 C/cm(2), and small stress-induced leakage current. This good oxide integrity is directly related to our previously developed SiGe formed by solid phase epitaxy at high temperatures that is stable during thermal oxidation. This simple process is fully compatible with existing very large scale integration technology.