A COMPARATIVE STUDY OF CONTACTS TO SILICON-GERMANIUM ALLOYS FOR SUB-100NM CMOS SOURCE/DRAIN JUNCTIONS

摘要

Recently, selectively deposited SiGeB alloys have been proposed to form ultra-shallow source/drain junctions for 35-70 nm CMOS. The technology provides super-abrupt junctions with above equilibrium dopant activation at temperatures less than 800℃. Another advantage of the technology is the lower bandgap of SiGeB, which has the potential of reducing the Schottky barrier height and hence, the junction contact resistance. This is a critical concern for future CMOS technology nodes since the contact resistance will dominate the MOSFET series resistance unless new technologies that result in contact resistivities near 10~(-8) Ω-cm~2 are developed. In this paper, we compare Ti, Co, Mo, Ta, W, Ni and Pt for the formation of self-aligned contacts to SiGeB alloys. The results show that Ni and Pt are promising candidates both yielding a contact resistivity near 10~(-8) ohm-cm~2.