Advanced silicide for sub-0.18 /spl mu/m CMOS on ultra-thin (35 /spl mu/m) SOI

Abstract

As CMOS device dimensions are scaled toward 0.1 /spl mu/m, formation of controllable thin silicide is critical. For conventional high temperature Ti salicidation, however, it is difficult to control silicide formation due to a fast reaction rate between Ti metal and silicon. Co silicide can achieve low sheet resistance for fine polysilicon lines and source/drain (S/D) regions, but the diode leakage is still a major problem with shallower junctions and SOI for deep sub-micron CMOS (Hsiao et al., 1998). In the past, a low temperature silicide technology has been proposed and applied to 100-nm SOI MOSFETs (Goto et al., 1995). In this paper, Ge/sup +/ pre-amorphized Ti salicide for sub-0.1 /spl mu/m gate length CMOS is investigated in detail and is used to demonstrate 0.1 /spl mu/m CMOS on an ultra thin SOI film of 35 nm for the first time. We focused on the influence of Ge/sup +/ pre-amorphization energy, Ti metal thickness and substrate doping on Ti silicidation kinetics, silicide depth and sheet resistance on bulk and fine polysilicon lines ranging from 1.0 to 0.1 /spl mu/m. Our results showed an effective control of silicide depth in the case of Ge/sup +/-implanted samples. A small grain size averaging 80 nm was observed on fine gate lines and polysilicon lines down to 0.1 m were shown to have good resistivity. The effects of metal thickness and doping species were eliminated. The excellent device performance shows this technology is highly suitable for future 0.1 /spl mu/m SOI MOSFETs and deep sub-micron bulk CMOS devices.