Basile Pottier, Felipe Aguilar, Mickaël Geitner, Francisco Melo, Ludovic Bellon, Journal of Applied Physics 129, 184503 (2021) – Editor’s Pick
[Article] doi: 10.1063/5.0040733
[Data set] doi: 10.5281/zenodo.4629591
When heated, micro-resonators present a shift of their resonance frequencies. We study specifically silicon cantilevers heated locally by laser absorption, and evaluate theoretically and experimentally their temperature profile and its interplay with the mechanical resonances. We include both elasticity and geometry temperature dependency, showing that the latter can account for 20% of the observed shift for the first flexural mode. The temperature profile description takes into account thermal clamping conditions, radiation at high temperature, and lower conductivity than bulk silicon due to phonon confinement. Thanks to a space-power equivalence in the heat equation, scanning the heating point along the cantilever directly reveals the temperature profile. Finally, frequency shift measurement can be used to infer the temperature field with a few percent precision.