GROWTH OF TISI2 FROM CODEPOSITED TISIX LAYERS AND INTERFACIAL LAYERS

The silicide formation characteristics from composition profiles creat ed on Si by codepositions was investigated. It was shown that a thin i nterfacial amorphous TiSix layer, with x similar to 0.5-1, deposited b etween Si and the Ti film led to a significant reduction in the observ ed C49-->C54 TiSi2 transformation temperature. The presence of the amo rphous interfacial TiSix layer slowed down the initial silicidation ra te, but promoted the nucleation of the final C54 TiSi2 phase. Predepos ition 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 demons trated for different temperature ramp rates and for a variety of subst rates including undoped alpha-Si, preamorphized n(+)-Si. and preamorph ized p(+)-Si. But this effect was found to be absent on single crystal Si. Possible mechanisms of the observed effects were discussed. (C) 1 997 American Institute of Physics.