Manipulation of the Ti/Si reaction paths by introducing an amorphous Ge interlayer

Evolution of the Ti/a-Ge/Si trilayer reactions has been investigated using transmission electron microscopy and four-point sheet resistance measurement. Instead of amorphous phase formation, as usually observed in the Ti/Si bilayer reaction, a crystalline Ti/sub 6/Ge/sub 5/ is the first phase observed during the reaction preceding the equilibrium C54-Ti(Si,Ge)/sub 2/, a substitutional solid solution type C49-Ti(Si,Ge)/sub 2/ forms upon annealing at 550/spl sim/600/spl deg/C, regardless of the replacement of amorphous phase by the crystalline phase. The C49-to-C54 polymorphic transformation occurs at /spl sim/650/spl deg/C. The reaction path is also correlated with the change in film resistance obtained from a-four-point sheet resistance measurement.