Fully-depleted SOI CMOSFETs with the fully-silicided source/drain structure

Abstract

A fully-depleted (FD) silicon-on-insulator (SOI) CMOSFET, whose source/drain (S/D) layers are completely silicided in depth with cobalt, have been successfully fabricated for the first time on a 20-nm-thick SOI layer using our advanced cobalt salicide technology. The fully-silicided S/D-nMOSFET and pMOSFET exhibit the same level of series resistance and significantly reduced bipolar junction transistor (BJT) action, compared to the conventional partially-silicided structure. The small series resistance is due to the small contact resistivity of CoSi/sub 2/ to both n/sup +/- and p/sup +/-diffusion layers, which are estimated to be on the order of low-10/sup -8/ /spl Omega/-cm/sup 2/ and high-10/sup -8/ /spl Omega/-cm/sup 2/, respectively. The improved BJT property is speculated to stem from the cobalt atoms diffused in the vicinity of the n/sup +//p junction, which can work as an effective lifetime killer. The fully-silicided S/D structures with CoSi/sub 2/ prove to be a valid structure for the FD SOI CMOS devices in the sub-0.13 /spl mu/m technology node.