Improvement of thermal stability of Ni germano-silicide for nano-scale CMOS technology

Abstract

In this paper, to enhance the thermal stability of the Ni germano-silicide especially on the doped substrate, various kinds of tri-layer structures of Ti/Ni/TiN, Ni/Ti/TiN, Co/Ni/TiN and Ni/Co/TiN were applied. Contrary to the conventional Ni silicide, two-step RTP is also applied to enhance the thermal stability of Ni germano-silicide. Among these structures, a highly stable Ni germano-silicide can be formed by Ni/Co/TiN with high Co concentration along with 2-step RTP. Co/Ni/TiN and Ti/Ni/TiN, especially Co/Ni/TiN with high Co concentration using 2-step RTP, are found to be effective in preventing the abnormal increase of sheet resistance on the As doped substrate during post-silicidation annealing higher than 613/spl deg/C.