Activation of silicon implanted with phosphorus and boron atoms by microwave annealing with carbon powder as a heat source

摘要

We report the activation of silicon implanted with phosphorus and boron atoms by microwave annealing using carbon powder as a heat source. Silicon substrates were covered with carbon powder and then irradiated with 2.45 GHz microwaves using a commercial microwave oven. Carbon powder effectively absorbs microwaves and heats itself at 1000℃. Silicon substrates are heated by thermal conduction. We carried out implantations of phosphorus atoms at a concentration of 1.0 × 10~(15)cm~(-2) at 75keV and boron atoms at a concentration of 1.0 × 10~(15)cm~(-2) at 25keV for p- and n-type silicon substrates, respectively. Microwave annealing at 1000 W for 120 s achieved sheet resistivities of 140 and 85Ω/sq for the phosphorus- and boron-implanted samples, respectively. It also realized the recrystallization of surface amorphized regions caused by implantation. Moreover, low surface recombination velocities of 3.8 × 10~2 and 2.7 × 10~2cm/s were obtained at the top implanted surfaces for the phosphorus- and boron-implanted samples, respectively. Typical diode rectified characteristics and solar cell characteristics with a conversion efficiency of 10.1% were successfully obtained.