Sub-10⁻⁹ Ω·cm² contact resistivity on p-SiGe achieved by Ga doping and nanosecond laser activation

Abstract

We report record breaking values for PMOS source drain (S/D) contact resistivity, ρ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> < 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> . These were obtained by shallow Ga ion implantation on Si <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.4</inf> Ge <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</inf> in combination with subsequent pulsed nanosecond laser anneal (NLA). Cross section transmission electron microscopy (XTEM) shows the pc reduction mechanism is based on Ga and Ge segregation towards the surface.