Electrical and structural properties of coevaporated NiSi_{2 ± x} thin films

Abstract

Electrical and microstructural changes of coevaporated amorphous NiSi2 ± x(x ~ 0.2) thin films were studied by means of in situ resistivity measurements and hot-stage transmission electron microscopy. The crystallization process is controlled by nucleation and growth both during continuous heating and isothermal annealing. Initially, the growth is isotropic. The process of crystallization is associated with a rapid decrease in resistivity. The temperature at which crystallization starts is affected by the heating rate. The temperature coefficient of resistivity (TCR) changes from a negative value in the amorphous state to a positive value in the crystallized state. Enriching the alloy film by silicon lowers the crystallization temperature. Kinetic studies showed that the isothermal crysallization follows a sigmoidal curve. The activation energy for the crystallization process was found to be ~ 1.45 eV. The transformation mode parameter was experimentally determined to be ~2. © 1989.