Retardation of arsenic diffusion in silicon-germanium by co-implantation

Abstract

We investigated the effect of silicon, argon and oxygen co-implants on arsenic diffusion in SiGe-on-insulator (SGOI). Arsenic diffusivity is enhanced roughly by a factor of 10 in 26% SGOI with respect to bulk silicon. At high doses, silicon co-implants significantly retard arsenic diffusivity such that the junction depths are similar to arsenic junction depth in bulk silicon. Argon co-implants significantly reduce arsenic diffusion at much lower doses than silicon co-implants with junction depths comparable to bulk silicon. XTEM reveals argon bubbles and a high density of stacking faults in argon co-implanted samples. These defects can act as sinks for vacancies and slow down arsenic diffusion. Oxygen co-implants also retard arsenic diffusion with junction depths comparable to bulk silicon at high oxygen doses. XTEM of the oxygen co-implanted samples reveals a high density of stacking faults, oxygen clusters and dislocation loops.