Vacancy Engineering – An Ultra-Low Thermal Budget Method for High-Concentration 'Diffusionless' Implantation Doping

This paper reviews the physics and the potential application of ion-implanted vacancies for high-performance B-doped ultra-shallow junctions. By treatment of silicon films with vacancygenerating implants prior to boron implantation, electrically active boron concentrations approaching 1021 cm-3 can be achieved by Rapid Thermal Annealing at low temperatures, without the use of preamorphisation. Source/drain (S/D) junctions formed by advanced vacancy engineering implants (VEI) are activated far above solubility. Furthermore, in the case of appropriately engineered thin silicon films, this activation is stable with respect to deactivation and the doping profile is practically diffusionless. Sheet resistance Rs is predicted to stay almost constant with decreasing junction depth Xj, thus potentially outperforming other S/D engineering approaches at the ‘32 nm node’ and beyond.