Evaluation Of Ni(Si1-xGex) and Pt(Si1-xGex) Contact Resistance for FD-SOI PMOS Metallic Source and Drain

Abstract

To improve 20nm FD-SOI pMOS transistor performances, salicide process must be optimized on SiGe source&drain. In this paper, we propose an investigation on Ni and Pt/Si1-xGex (x=0.15, 0.3) systems. In a first part, process window is studied to determine thermal budget domain where the less resistive phase is stable morphologically and thermically. Solid state reactions in terms of phase sequence, thermal stability and morphology have been examined. At high temperature, two kinds of degradations have been observed. In Ni case, Ge out diffusion leads to the film agglomeration. In Pt case, grain coalescence degrades germanosilicide film. In a second part, contact resistivity has been extracted on lateral germanosilicides thanks to new designed structures. After a validation on Pt/Si system, RC extraction has been carried out on Si1-xGex substrate up to 30% of Ge. RC seems to be better with Pt compared to Ni with the same conditions of process optimizations.