Effect of strain on the oxidation rate of silicon germanium alloys

We report on a series of experiments in which a strained Si0.95 Ge0.05 layer 600Å thick was oxidized along with relaxed SiGe layers and Si samples. In this work, we observed that the oxidation rate of the strained SiGe layer is always much higher than the relaxed model expectations. We also observed that the rate is higher than that of relaxed SiGe layers with higher Ge concentration oxidized at similar temperatures. We attributed this increase in the rate of oxidation to the effect of strain in the SiGe layer. To confirm our hypothesis, we oxidized strained SiGe layers together with relaxed SiGe layers of higher concentration. We observed that the strained SiGe layer compared with relaxed sample has a thicker oxide despite the lower Ge concentration. We conclude that the strain in the SiGe layer causes a further increase in the oxidation rate.