Noninvasive measurement and control of the temperature of Pt nanofilms on Si supports

A direct, noninvasive thermometry method based on the temperature dependence of the in-plane electrical resistance R(T) of 20 nm Pt films on Si-based semiconducting substrates is presented. At the calibration stage, the entire sample is slowly heated or cooled by external means. For moderately doped semiconductors, the R(T) dependence is closely linear at low temperatures (T < 300 K), when the nanofilm metal conductance dominates, followed by a maximum and a subsequent decrease attributed to an increasing substrate conductance at higher temperatures. The position of the maximum depends on the Pt–substrate interface conditions, in particular, on the presence of an oxide layer, and may vary from 350 to 500 K. With the R(T) dependence measured in equilibrium one can derive T(R), which provides a highly accurate method for noninvasive measuring and controlling the temperature of the nanofilm with a direct resistive heating technique. Accuracy of the present method for dynamical measurement is shown to be significantly better than that of a standard approach using a Pt resistance temperature detector attached to the nanofilm for heating rates of 1–7 K/s.