The Top Silicon Layer of SOI Formed by Oxygen Ion Implantation

High dose oxygen ion implantation has been used to form a buried oxide layer in Czochralski grown silicon. Wafers were implanted with 300 keV O2+ to a total dose of 1.32 × 1018 ions cm-2. A 0.5 m thick SiO2 layer is formed beneath a 0.17 ¿m thick top Si layer. Epitaxial films were grown on both annealed and unannealed wafers. Samples were subsequently annealed at 1150°C for times from 10 to 240 minutes in either Ar or N2. The highest quality epitaxial layers were obtained with substrates that were annealed after implantation, but prior to epitaxial growth for 2 hrs at 1150°C followed by 4 hrs at 1150°C after epitaxial growth. RBS channeling shows that the top 300 nm of these films have <110> channel backscattering yields lower than any SOI produced to date. The buried oxide plus epitaxial process is a leading candidate for VLSI applications.