Effects of Mo-free C40Ti(Si1-xGex)(2) precursors and the thickness of an interposed Mo layer on the enhanced formation of C54Ti(Si1-xGex)(2)

Abstract

The effects of Mo-free C40 Ti(Si1-xGex)(2) precursors and the thickness of an interposed Mo layer between Ti films and Si0.76Ge0.24 substrates on the lowering of formation temperature of C54 Ti(Si1-xGex)(2) were studied. Metastable C40 Ti(Si1-xGex)(2) precursors were grown by pulsed KrF laser annealing. Upon rapid thermal annealing, the Mo-free C40 phase could not be directly transformed to the C54 phase without going through the C49 phase. When the thickness of the interposed Mo layer increased, up to 2.5 nm, the temperature at which the C54 phase was initially formed changed from 750 to 600 and then to 650 degrees C. The present result showed that with increasing Mo concentration in the reacted layer, the phase stability shifted from C54 to C40 and no C49 was observed. It seems that apart from the C40 template mechanism, the electron/atom ratio also plays an important role in the enhanced formation of the C54 phase. (C) 1999 American Institute of Physics. [S0003-6951(99)02048-3].