Enhancement of boron solid solubility in Si by point-defect engineering

The technique of point-defect engineering (PDE), with excess vacancies produced near the surface region by MeV Si ion implantation, has been applied to form ultrashallow junctions with sub-keV B implants. PDE can reduce boride-enhanced diffusion that dominates the enhanced diffusion of ultralow energy B implants. PDE can further sharpen the dopant profile and enhance boron activation. For 1×1015/cm2, 0.5 keV B implant, B solid solubility has been enhanced over a wide temperature range of 750–1000 °C, with an enhancement factor of 2.5 at 900 °C. These features have enabled a shallower and sharper box-like boron junction achievable by PDE in combination with ultralow energy 0.5 keV B implantation.