High dopant activation of phosphorus in Ge crystal with high temperature implantation and two step microwave annealing
In this letter, high temperature ion implantation and low temperature microwave annealing were employed to achieve high n type active concentrations, approaching the solid solubility limit, in germanium. To use the characteristics of microwave annealing more effectively, a two step microwave annealing process was employed. In the first annealing step, a high power (1200 W; 425 degC) microwave was used to achieve solid state epitaxial regrowth and to enhance microwave absorption. In the second annealing step, contrary to the usual process of thermal annealing with higher temperature, a lower power (900 W; 375 degC) microwave process was used to achieve a low sheet resistance, 78O/ and a high carrier concentration, 1.025 x 1020 P/cm3, which is close to the solid solubility limit of 2 x 1020 P/cm3.