SILICIDE FORMATION BY CONCENTRATION CONTROLLED PHASE SELECTION

It is proposed that direct formation of epitaxial CoSi2 and NiSi2 as t he first phase, is due to the interlayer between the metal and silicon acting as a diffusion barrier, which decreases the metal concentratio n at the growth interface. Such concentration controlled phase selecti on (CCPS) is explained thermodynamically by utilizing the effective he at of formation (EHF) model. This approach is also used to explain sil icide formation with metal alloys. Concentration controlled phase sele ction (CCPS) is not only applicable to silicide formation but should i n general enable materials scientists to form phases with desirable pr operties, by controlling the concentrations of the reactants at the gr owth interface. (C) 1997 American Institute of Physics.