Interfacial reaction of Si islands on SiO_2 during high-temperature annealing

摘要

We examine the interfacial reaction between submicron Si islands and SiO_2 during high-temperature annealing under ultrahigh vacuum, using atomic force microscopy and transmission electron microscopy. We show that Si island/SiO_2 interfaces are much more reactive than interfaces of wetting thin Si films on SiO_2. This indicates that important processes responsible for the reaction occur at the Si island edges. During the reaction removal of O atoms from the SiO_2 side of the interface, occurs, resulting in depression of the Si island/SiO_2 interface. Our observations indicate that the interfacial reaction advances via O out-diffusion from SiO_2 into the Si island, O lateral diffusion along the interface, SiO formation at the edge of the Si island, and SiO desorption from the surface.