Titanium Interlayer Mediated Epitaxy of CoSi 2 on Si 1− xGe x

Abstract

Titanium Interlayer Mediated Epitaxy (TIME) has been shown to promote the formation of epitaxial CoSi 2 on Si (100). Similarities between Si and Si 1− x Ge x alloys have motivated a study of whether the TIME process could be successful in forming epitaxial CoSi 2 on Si 1− x Ge x . Titanium layers of varying thickness were deposited as interlayers between a Co layer and c-Si/Si 0.8Ge 0.2 grown epitaxially onto Si (100) to investigate their role in the formation of epitaxial CoSi 2 on Si 1− x Ge x alloys. The effect of Ti interlayer thickness on the orientation of CoSi 2 to the Si 1− x Ge x substrate, and the conditions under which a polycrystalline CoSi 2 film has been formed have been studied. It was found that Ti was beneficial in promoting epitaxy to the substrate in all cases. The experimental results indicate that with a Ti interlayer thickness of ∼ 50 Å, the formation of epitaxial CoSi 2 adjacent to the substrate was achieved, and pinhole formation was minimized. It was also observed that for increased interlayer thickness, Ti reacted with Si to form a titanium silicide.