Strain sensitivity of TiB2, TiSi2, TaSi2 and WSi2 thin films as possible candidates for high temperature strain gauges

The boride TiB2 and the silicides TiSi2, TaSi2 and WSi2 are known for some specific high temperature applications. However, their ability to strain gauge technology has not been tested so far according to the authors’ knowledge. The four conductive ceramics were sputter deposited onto silicon and alumina substrates with film thicknesses between 140 and 720 nm. Their specific resistance (ρ), temperature coefficient of resistance (TCR) and gauge factor (k) were determined at a maximum temperature of 300 °C. The ρ's are significantly higher than the literature bulk values and all TCR's are negative. This behaviour indicates a partly non crystalline yet disordered structure of the films. The gauge factors are in the range of 1.1–2.2 on silicon. In particular TiB2 seems interesting, since its TCR is near zero (−50 pp mK−1)-independent of the examined sputtering conditions.