Diffusion of impurities from ion implants in silicon

Abstract

The use of shallow single and double impurity ion implants as diffusion sources was studied on bare (111) silicon wafers implanted at room temperature with 45 KeV boron, phosphorus and arsenic. The samples were diffused in a vacuum from 900'^C to I llOO^C. The experimental diffusion profiles were wel 1 approximated by a gaussian distribution, except near the surface. It was determined that for single diffusions about 50% of the arsenic, 60% of the phosphorus and al1 of the boron ions became electrically active after diffusion. Within experimental error, there was no interaction evident between the simultaneously diffusing arsenic and boron. The values of the diffusion coefficients obtained were within the wide range of values quoted in the literature. Some of the data presented in this thesis has been published in a paper by: H. Heinrich, L. Hastings and J. Rozenbergs, entitled: simultaneous Diffusion of lon-predeposited As and B in Silicon, in the Journal of Applied Physics, October 1974.