Ultralow-resistivity CMOS contact scheme with pre-contact amorphization plus Ti (germano-)silicidation

Abstract

Following the previous study on Si:P [1], we also achieve ultralow contact resistivities (ρ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> ) of ∼2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−9</sup> Ω·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> on Si <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</inf> Ge <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.7</inf> :B using the same Ti based pre-contact amorphization (PCAI) plus post-metal anneal (PMA) technique. Similar as on Si:P, low-energy PCAI provides the lowest ρ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> on SiGe:B. By increasing the B concentration, the PMA temperature required on SiGe:B also matches with that on Si:P. A simple Ti based CMOS contact flow is thus proposed. Several B doping and activation methods on SiGe:B are also compared in this work.