Activation of B and As in Ultrashallow Junction During Millisecond Annealing Induced by Thermal Plasma Jet Irradiation

Abstract

We have investigated effects of annealing temperature and heating and cooling rates during millisecond annealing on the activation of B and As in the Si lattice. In the case of As+-implanted samples, efficient dopant activation was observed at a temperature higher than 1000 K, while it was observed at a temperature higher than 1400 K in the case of B-implanted samples. The sheet resistance (RS) of B-implanted samples monotonically decreases with temperature, and no significant dependence on heating rate (Rh) or cooling rate (Rc) is observed. On the other hand, As+-implanted samples show significant dependence of RS on Rh and Rc. We have performed thermal plasma jet (TPJ) annealing on an As2+-implanted sample, and obtained an ultrashallow junction (USJ) with a junction depth (Xj) of 11.9 nm and a RS of 1095 Ω/sq. B USJ is also obtained with a Xj of 23.5 nm and a RS of 392 Ω/sq. Precise control of Rh and Rc in addition to annealing temperature is quite important for achieving highly efficient doping in USJ.