Shallow donors in silicon coimplanted with rare-earth ions and oxygen

Abstract

Formation processes of shallow donors in Czochralski-grown silicon coimplanted with rare-earth ions and oxygen are studied. There is no indication that rare-earth ions are components of the structures of shallow donors. However, intrinsic defects appear to be involved in the formation processes. These oxygen-related thermal donors survive even at T=900°C. They are responsible for the electrical conductivity in the implanted layers at cryogenic temperatures.