EFFECT OF FLUORINE ON THE DIFFUSION OF THROUGH-OXIDE IMPLANTED BORON IN SILICON

Annealing of boron through-oxide implanted silicon has been known to induce an incubated, oxygen-precipitation enhanced boron diffusion. In this letter, it is shown that annealing the "through-oxide" implants in a NF3-containing N2 ambient effectively reduces the incubated enhanced diffusion. The effect of fluorine is further demonstrated for boron plus fluorine through-oxide implants with pure N2 annealing. Comparing the boron diffusion between boron plus fluorine and boron plus neon implants suggests that fluorine does not have a chemical effect on capturing the point defects that cause the enhanced diffusion. Rather, fluorine is believed to be incorporated in the oxygen precipitates, which alters the point defect generation.