Dynamic behavior of a silicon oxide layer on silicon ultrafine particles

In order to clarify the high-temperature behavior of a silicon oxide layer on the surface of Si ultrafine particles, the oxide layer has been studied using the atomic-resolution high-temperature stage of a transmission electron microscope. The natural oxide layer grown on Si ultrafine particles by exposure to air was an amorphous silicon oxide layer with a thickness of 1.5 nm. This oxide layer started to dissolve into the Si crystal upon heating at 500°C, and was fully dissolved into the Si crystal at 600°C in vacuum. When the specimen was cooled back to room temperature, the silicon oxide layer reappeared on the Si surface. This phenomenon, which can be detected only at high temperatures, is presented in this paper.