Growth and electrical properties of in situ Sb-doped Ge_(1-x)Sn_x epitaxial layers for source/drain stressor of strained-Ge transistors

摘要

We have investigated the thermal stability of heavily Sb-doped n(+)-Ge and n(+)-Ge0.94Sn0.06 epitaxial layers grown on a Ge substrate by annealing up to a temperature of 400 degrees C. The Ge0.94Sn0.06 sample with a Sb concentration higher than 10(20)cm(-3) retained superior crystallinity and a smooth surface even after annealing. It also maintained an electron concentration higher than the solid solubility of Sb and the highest substitutional Sb concentration after 400 degrees C annealing. We found the possibility of a low-contact-resistivity device employing Ge(0.94)Sn(0.04)with a high electron concentration and a metal with an electrode fabrication temperature lower than 400 degrees C. (C) 2018 The Japan Society of Applied Physics