Quality of SiO2 and of SiGe formed by oxidation of Si/Si0.7Ge0.3 heterostructure using atomic oxygen at 400 deg. C

The oxidation of a 2.7-nm-thick layer of Si formed on a layer of Si0.7Ge0.3 using atomic oxygen at 400 deg. C was studied with the aid of angle-resolved X-ray photoelectron spectroscopy and high-resolution Rutherford backscattering spectroscopy. Analysis of the measurement results revealed that: (1) an appreciable number of Ge atoms diffused into the Si layer during the formation of a 3-nm-thick Si layer on the Si0.7Ge0.3 layer at 720 deg. C; (2) when the entire Si layer was oxidized, 1.8% of the Si layer remained in the SiO2 in the form of Si0.7Ge0.3 alloy; and (3) an abrupt compositional transition took place at the SiO2/SiGe interface