Dozens of small dual-beam thin-film temperature sensors with a total width down to 430 nm were fabricated and tested. The sensors were all made from 90-nm-thick Pd thin films, where the width of the narrow stripes was 70-100 nm and that of the wide ones was 210-800 nm. Two different calibration methods showed consistent and repeatable sensitivities of 0.7-1.2 μV/K for the sensors, confirming that the sensitivity mainly depended on the width configuration of each sensor. By integrating arrays of such sensors on a practical testing platform using hybrid e-beam lithography and photolithography techniques, we demonstrated that these sensors were capable of detecting a weak surface temperature difference of 0.1-0.2 K at microscale, and they could be scaled up as built-in temperature sensors in many practical devices.
Keywords: Built-in temperature sensor; Nanostripe; Sensitivity; Submicron thermometry; Thin-film.