Point defect/dopant diffusion considerations following preamorphization of silicon via Si+ and Ge+ implantation

Abstract

A comparison has been made between two shallow preamorphization techniques using Si+ and Ge+ implantation, followed by B+ implantation and rapid thermal annealing (RTA). The subsequent impact on boron diffusion profiles and extended defects have been examined experimentally with secondary ion mass spectroscopy and cross-section transmission electron microscopy, and theoretically with the predict computer program, in an attempt to generalize the observations. Enhanced or retarded B diffusion during RTA has been correlated with the relative depths of the original amorphous/crystalline interface and the as-implanted B profiles, with ion type used for preamorphization, and with the initial type and relative location of the radiation-induced point defects. In general, Si+ self-implant samples showed less B profile broadening than Ge+ implant samples following RTA at 1050 °C for 10 s. The conditions necessary for complete annihilation of end-of-range interstitial loops for Si+ self-amorphization are specified.