Dopant Activation in Single-Crystalline Germanium by Low-Temperature Microwave Annealing

Phosphorus activated in germanium epitaxy atop Si wafer by low-temperature microwave annealing technique was investigated in this letter. Compared to the conventional RTA process, the temperature of phosphorus activation could be 120°C to 140°C which is an improvement in temperature reduction at the same sheet resistance. According to the SRP, up to 150°C reduction in maximum temperature at the same activation concentration (about 2 × 10¹⁹ cm^-3) could be achieved. Through adjusting the microwave power and process time, sheet resistance could be decreased while suppressing dopant diffusion. In addition, the inserted susceptor wafers above and below the processing wafer also suppressed the dopant diffusion and improved film roughness.