Low temperature characterization of heated microcantilevers

This article describes the electrical and thermal behaviors of heated atomic force microscope cantilevers under steady- and periodic-heating operation at low temperatures and in vacuum. The cantilever resistance drastically increases as temperature decreases below 150 K, providing a large and negative temperature coefficient of resistance of -0.023 K-1 at 100 K. Under steady heating, the cantilever heater can be heated above 300 K even when its environment is at 77 K. Electrical and thermal transfer functions are derived to depict the electrical and thermal cantilever responses under periodic heating and to extract cantilever thermophysical properties. The calculation of in-phase and out-of-phase temperatures along the cantilever reveals that its response becomes out of phase and restricted to the heater region at high frequencies. These results enable the use of heated cantilevers in cryogenic applications as a localized heat source and a sensitive thermal metrology tool.