Orientation-dependent stress build-up during the formation of epitaxial CoSi2
The epitaxial CoSi2 is formed by using a Ti interlayer with variable thickness on a (100) Si substrate (TIME: Ti interlayer mediated epitaxy). These experiments confirm previous work where for an increasing amount of Ti in between the Si substrate and the Co layer, a transition from polycrystalline CoSi2 over a preferential (220) orientation towards (400) epitaxial CoSi2 is observed. This work emphasises the impact of the volume fraction of the epitaxial (400) CoSi2 grains on the mechanical stress induced during the Si/Ti/Co silicidation. It is shown that the mechanical stress increases for increasing epitaxial (400) orientation of the CoSi2 film. The stress caused by the epitaxial CoSi2 can have a detrimental impact on the device performance.
epitaxial cosi2 mechanical stress stress relaxation mechanisms