Two‐step rapid thermal annealing of B‐ and As‐implanted polycrystalline silicon films

We investigate the electrical properties of polycrystalline silicon films implanted with boron or arsenic at doses 4×1014, 8×1014, and 5×1015 cm−2, respectively. Two post‐implantation rapid thermal annealings (RTAs) have been performed: a standard one‐step RTA (1150 °C, 20 s) and a two‐step RTA (1150 °C, 4 s+680 °C, 4 min). We find that the electrical behavior depends on the implanted species. Boron‐implanted films exhibit the highest electrical properties (high dopant activation and mobility). The trap density Nt at grain boundaries is found to be independent of the heat treatment.