First-principles density-functional calculations were performed in order to study the stability of donor-pair defects at Si/SiO2 interfaces. For P dopants, individual dopant atoms energetically favored Si lattice sites in the interface region; as compared to bulk SiWhen dopant atoms aggregated to the interface region at very high dopant concentrations, dopant segregation occurred in the form of an electrical deactivation of nearest-neighbor donor pairs that comprised 2 threefold coordinated dopant atoms. This defect model explained both the redistribution and deactivation of dopant atoms observed at Si/SiO2 interfaces.

Segregation of Nearest-Neighbor Donor-Pair Defects to Si/SiO2 Interfaces. Y.S.Kim, K.J.Chang: Applied Physics Letters, 2005, 87[4], 041903 (3pp)