Activation of Implanted Boron Atoms in Silicon Wafers by Infrared Semiconductor Laser Annealing Using Carbon Films as Optical Absorption Layers

Abstract

We report continuous wave (CW) IR semiconductor laser annealing for the activation of boron atoms implanted into an n-type Si wafer with diamond-like carbon (DLC) films as optical absorption layers. Boron atoms were implanted at 10 keV at doses of 5×1014, 1×1015, and 1.5×1015 cm-2. The depth at the boron concentration of 1018 cm-2 was 50 nm. Samples were annealed by irradiation at 66.5–80.5 kW/cm2 and 2.6 ms. The sheet resistance of the sample markedly decreased to 531 Ω/sq for implantation at 1.5×1015 cm-2 by laser annealing. Boron atoms were almost completely activated at a carrier density near the boron concentration for implantation at 10 keV. The largest diffusion length of boron atoms was 3 nm.