Alternative pathway for the formation of C54TiSi2

The influence of interfacial Mo on the formation of TiSi2 is studied using 120 nm Ti layers deposited on Si (100) substrates. After annealing at 450 degrees C, C54 TiSi2 and C40 (Ti,Mo)Si-2 are found in the samples initially having an interposed layer of Mo 1.6-2 nm thick. In the absence of Mo, only C49 TiSi2 is obtained. The pathway for the formation of C54 TiSi2 is altered from the usual C49-C54 phase transformation to the epitaxial growth of C54 TiSi2 on C40 (Ti,Mo)Si-2. The resistivity of the TiSi2 layers formed is about 14 and 61 mu Omega cm for the C54 and C49 phase, respectively. However, for equal annealing time, the thickness of the C49 TiSi2 formed is about ten times that of the C54 TiSi2 grown on C40 (Ti,Mo)Si-2, because of the barrier effects on Mo or C40 (Ti,Mo)Si-2 on Si diffusion. The experimental results are discussed on the basis of energetic arguments to account for the suppressed formation of C49 TiSi2 and the enhanced formation of C54 TiSi2 at 450 degrees C. (C) 1999 American Institute of Physics. [S0021-8979(99)02513-X].