Thermal Sensing With Lithographically Patterned Bimetallic Thin-Film Thermocouples

A chromium-nickel thin-film thermocouple that is 50 nm thick is demonstrated on a semiconductor substrate as proof of concept for lithographically processed bimetallic on-chip temperature sensors. The Seebeck coefficient of the thin-film thermocouple is calibrated to be 10.37 μV/°C, reproducibly smaller than the bulk literature value by a factor of 3.98. The batch reproducibility of this thin-film Seebeck coefficient is demonstrated. The linear Seebeck response up to 90°C is calibrated with the help of a simple formula which accounts for the temperature variations of the reference thermocouple under large heat loads.