High quality Si-on-SiO₂ films by large dose oxygen implantation and lamp annealing

Ion beam synthesis of a buried SiO₂ layer is an attractive silicon-on-insulator technology for high-speed complementary metal-oxide-semiconductor circuits and radiation hardened devices. We demonstrate here a new annealing procedure at 1405°C that produces silicon films of excellent quality, essentially free of oxygen precipitates and with sharp interfaces between the Si and the SiO₂. Buried oxide layers have been formed in Si (100) wafers by implanting 400 keV molecular oxygen at 500°C to a dose of 1.8×10¹⁸ cm^{- 2}. Annealing was performed by radiative heating of the back side of each sample to the melt temperature of silicon, T_M=1412°C, so that the buried oxide structure was at 1405°C. The temperature control relies entirely on the change in optical properties of silicon upon melting. This ensures, without any external feedback, that the surface exposed to the photon flux will remain at T_M.