Electron cyclotron resonance plasma oxidation of strained Si on relaxedSi1−xGexbuffer layers inO2ambient at room temperature is reported. The electrical properties of grown oxide have been characterized and compared with thermally grown oxides using a metal-oxide semiconductor structure. At a low field, the accumulation of holes in the buriedSi1−xGexlayer, due to the type-II band offset, has been observed. The experimental results from thermally grown oxides have been compared with the simulation results obtained using a heterostructure Poisson solver. ©1997 American Institute of Physics.