A study of the sheet conductance profiles for recoil-implanted n-type silicon

Recoil implantation provides an alternative means to form very shallow and highly doped surface layers. This work examined the recoil implanted sheet conductance profiles in n-Si. Both Co and Al dopants were used. The sheet conductances were measured using the standard four-point probe technique and the profiles were obtained by successive anodic oxidation and etching of the implanted layers. The data were compared with simulated results based on reported recoil dopant profiles. A surface coordinate adjustment was needed to provide a good match. This seems to be closely related to the difficulty in identifying the Si surface after the implantation. On the whole, the sheet conductances appeared to provide a reasonable estimation of the surface carrier densities. (author)