Abstract
The use of shallow ion implants as diffusion sources was studied on bare (111) silicon wafers implanted at room temperature with 30 keV, 3·1014 cm−2 boron. Samples were annealed in purified argon at 900°, 1000°, and 1100°C. The diffusion profiles of boron are determined by in‐diffusion into the silicon and by dissolution, to equilibrium, in the thin oxide layer on the surface. The amount of boron retained in silicon decreases during the initial period of an anneal and then remains constant. More boron is retained the higher the temperature and the lower the oxygen content in the ambient gas. With ∼10 ppm O2 in argon, losses range from 15 to 35% of the implanted dose. Experimental results are reasonably well represented by the mathematical formalism developed. The experimental data indicate that the values listed in the literature for sheet conductivity mobilities of holes are too low.