Study of interfacial defects induced during the oxidation of ultrathin strained silicon layers

In this work ultrathin strained silicon layers grown on relaxed Si0.9 Ge0.1 substrates were oxidized under high thermal budget conditions in N₂ O ambient at 800 °C. The results indicate that the density of interface traps depends on the extent of the oxidation process. If the strained Si layer is totally consumed the density of interface traps reduces to almost half the value as compared to the case where a part of the strained Si layer still remains. The results indicate that the two existing interfaces of the strained Si layer, the SiO₂ /strained-Si and the strained- Si/ Si0.9 Ge0.1, contribute in parallel to the measured interface trap density. In addition, the buried strained- Si/ Si0.9 Ge0.1 interface constitutes a major source of the observed high density of interface traps.