High Dopant Activation and Diffusion Suppression of Phosphorus in Ge Crystal with High-Temperature Implantation By Two-Step Microwave Annealing

In this Letter, high-temperature ion implantation and low-temperature microwave annealing were employed to achieve maximum n-type active concentration, which can be fully activated in germanium. To use the characteristic of microwave annealing more effectively, two-step microwave annealing was also employed. In the first step annealing, a high-power (1200 W; 425 °C) microwave was used to achieve solid-state epitaxial regrowth (SPER) and enhance microwave absorption. In the second step of annealing, unlike in conventional thermal annealing, which requires a higher energy to activate the dopant, a low-power (900W;375 °C) microwave was used to achieve lowest sheet resistance 78Ω/□ and maximum active concentration 1.025×1020 P/cm3, which close to its solid solubility limit of 2×1020 P/cm3.