B activation enhancement in submicron confined implants in Si

We implanted $3keV$ B ions into a crystalline Si film, grown by molecular-beam epitaxy and masked by $SiO2$ stripes with opening widths ranging from $3.2μm$ down to $0.38μm$⁠. Thermal anneals were performed at $800°C$ for several times. By quantitative high-resolution scanning capacitance microscopy, we demonstrated that the electrical reactivation of inactive B after postimplant annealing is obtained at faster rates as the window width decreases. Total electrical activation is gained first in the narrowest window, with times shorter by nearly a factor of 4 compared to the widest one. In addition, since inactive B seems to be caused by B clustering induced by implantation, our results put in evidence a strong effect of implantation confinement also on B clusters dissolution mechanism. These results have a strong impact on the modern silicon-based device engineering.