Reflection-high-energy-electron-diffraction intensity oscillations of Si(111) during gas source molecular beam epitaxy

Reflection-high-energy-electron-diffraction (RHEED) intensity oscillations were used to monitor Si(111) growth during gas source molecular beam epitaxy using disilane. Intensity oscillations were measured as a function of both substrate temperature and disilane flow rate. Within the substrate temperature range of 490–560 °C where growth proceeded two dimensionally, well-defined intensity oscillations corresponding to bilayer growth could be observed along the [21̄1̄] and [11̄0] azimuths. The oscillation frequencies were found to increase with increasing substrate temperature as well as disilane flow rate. At lower temperatures where no dissociative adsorption of disilane occurred, intensity oscillations were not observed. At higher temperatures, growth entered the step flow regime and the intensity oscillations were weak or absent.