Microwave plasma oxidation (below 200 °C) of strained Si on relaxedSi1−xGexbuffer layers inN2O ambient is reported. The electrical properties of grown oxide have been characterized using a metal-oxide-semiconductor structure. Fixed oxide charge density and mid-gap interface state density are found to be6×1010 cm−2and1.2×1011 cm−2 eV−1, respectively. The oxide on strained-Si samples has exhibited hole trapping behavior and moderately low interface state generation on constant current stressing. ©1997 American Institute of Physics.