Platinum silicide formation on Si_1-yC_y epitaxial layers

This study first investigates the formation of Pt silicides on Si _1-yC_y (y = 0.024) epilayers in the presence of an interfacial oxide layer. The presence of C atoms is found to retard the growth kinetic of PtSi but significantly improve the thermal stability of PtSi thin films. Experimental results also indicate that an interfacial oxide layer present at the initial Pt/Si_1-yC_y interface should have no negative impact on the subsequent Pt silicidation in terms of process integration. We also propose a mechanism to discuss the relationship between microstructures, electrical property, and thermal stability of Pt silicides in terms of C solubility in PtSi. In this mechanism, C atoms accumulated at the PtSi grain boundaries may act as diffusion barriers, which effectively inhibit the grain growth and agglomeration of PtSi and thus widen the low-resistivity process window of PtSi. More importantly, it is possible to gain the benefits of excellent thermal stability of PtSi silicides and enhanced tensile strain in Si_1-yC_y epilayers simultaneously if the thermal budget is well controlled during the silicidation process.