Effect of Pt on agglomeration and Ge out diffusion in Ni(Pt) germanosilicide

The effect of Pt alloy in Ni (Pt∼5 and 10 at. %) on the agglomeration and Ge out diffusion in nickel germanosilicide formed on Si0.75 Ge0.25 (100) has been studied. A remarkable improvement in the agglomeration behavior with increasing Pt atomic percentage is observed by sheet resistance measurements while still maintaining Ni(Pt) monogermanosilicide phase between 400 and 800 °C. Ge out diffusion from the monogermanosilicide grains has been suppressed up to a temperature of 700 °C with the addition of Pt, evident by x-ray diffraction and micro-Raman spectroscopy. In addition, that improvement of surface morphology and suppression of Ge out diffusion with increasing Pt atomic percent is also confirmed by Rutherford backscattering and cross-sectional transmission electron microscopy. The improved morphology and agglomeration are explained by a grain-boundary model which includes kinetic effects. The suppression of Ge out diffusion from the germanosilicide grains is attributed to reduced atomic diffusion and the presence of stronger Pt-Si and Pt-Ge bonds due to the addition of Pt.