TiC and TaC thin films were investigated, for the first time, for thin film thermocouple applications. Thin films of TaC and TiC were deposited on electronic grade alumina substrates using the r.f. sputter deposition technique. Sheet resistance of the thin films was measuring a four point probe. It was observed that the sheet resistance of the films depends critically on the deposition parameters such as substrate temperature during deposition, sputter gas pressure and r.f. power used. Thedeposition parameters were optimized to yield the lowest sheet resistance of the thin films at room temperature. The thermoemf of the deposited films was measured as a function of temperature vacuum using a home made device. It was observed that thinfilms of TaC and TiC yield fairly high and stable thermoemf throughout temperature range of stability. Under the optimized deposition conditions, thin film thermocouples were fabricated. The thermocouples were calibrated against temperature and the output was measured in vacuum (pressure < 10{sup}-6 TOrr). TiC/TaC thermocouples yield stable output up to 1350 K, temperature above which breakdown occurs. The thermocouple output was theoretically estimated from the thermoemf measured, and compared. It wasobserved that these thermocouples yield reproducible output in the temperature range of stability and hold excellent potential for high temperature thin film temperature sensor applications in vacuum or inert atmospheres.
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