Effect of double-layered sio₂-si₃n₄ films on formation of stacking fault-free region in silicon

We have studied the effect of surface conditions on the formation of a stacking fault-free region. The specimens with and without double-layered SiO₂-Si₃N₄ films were heat-treated at 750°C for 64 h and then annealed in vacuum at 1050-1150°C for 0.5–128 h. In the specimens with double-layered films, a stacking fault-free region was formed beneath the Si-SiO₂ interface, while it was formed beneath the surface in the bare specimens. Its thickness increased depending on the annealing time, t^0.6±0.1. The thickness of the stacking fault-free region in the bare specimens was two to three times wider than that in the specimens with double-layered films. This difference can be explained using a model in which the Si-SiO₂ interface acts as a sink of self-interstitials and the bare surface acts as not only a sink of self-interstitials, but also as a source of vacancies.