Growth of TiSi2 from codeposited TiSix layers and interfacial layers

Abstract

The silicide formation characteristics from composition profiles created on Si by codepositions was investigated. It was shown that a thin interfacial amorphous TiSix layer, with x∼0.5–1, deposited between Si and the Ti film led to a significant reduction in the observed C49→C54 TiSi2 transformation temperature. The presence of the amorphous interfacial TiSix layer slowed down the initial silicidation rate, but promoted the nucleation of the final C54 TiSi2 phase. Predeposition and preannealing were also found to facilitate the growth of C54 TiSi2, as was growth from codeposited full TiSix layers with Ti-rich compositions. The efficacy of the (interfacial) TiSix layer was demonstrated for different temperature ramp rates and for a variety of substrates including undoped α-Si, preamorphized n+-Si, and preamorphized p+-Si. But this effect was found to be absent on single crystal Si. Possible mechanisms of the observed effects were discussed.