Thermal properties of Cr- and Ni-silicide thin films

New types of functional thin films of Cr-Si and Ni-Si were fabricated for heating element applications. In order to reduce the problem of large variations of electrical resistance of heating elements during the semiconductor thermal processing, we attempt to minimize temperature coefficient of resistance (TCR) of the heating material by mixing the semiconductor and metallic materials. As the heating elements, two different multi-layered structures were prepared by RF magnetron sputtering technology; Cr-Si and Ni-Si structures on top of Al2O3 substrates. The thickness of the Cr-Si and Ni-Si Films ranged up to a couple of micron, and a post annealing at 750 degrees C was carried out to achieve more reliable film structures. The electrical and thermodynamic properties of the thin films were measured up to the temperature of 500 degrees C. Chrome-rich films show the metallic properties, whereas silicon-rich films do the semiconductor properties in measurements of TCR. Optimal composition between chrome and silicon has been obtained as 2:1 in the Auger electron spectroscopy analysis. TCR for the sample was estimated as about +0.0003/degrees C-1, which is fairly low value when considering the conventional heating elements.