Temperature-dependent thermomechanical noise spectra of doped silicon microcantilevers

This paper reports temperature-dependent thermomechanical noise spectra of boron-doped silicon microcantilevers over the temperature range of 25-175 °C and cantilever power up to 75 mW. Either local heating from integrated solid state resistors or uniform heating on a hotplate were employed. Using a cantilever with oxide residue, the temperature coefficient of the resonance frequency was 1.10 × 10^-4 °C^-1 for uniform heating and 2.84 × 10^-4 °C^-1 for local heating. Local heating thus modulated the resonance frequency more dramatically than uniform heating. For the oxide-coated cantilever, the cantilever resonance frequency increased with increasing temperature. However, when the oxide was removed, the resonance frequency decreased with increasing temperature. By employing two cantilever types having different doped resistors, three different thermal loadings characterized by the temperature gradient were investigated. When the highest temperature was at the cantilever base, the cantilever mechanical properties were more highly affected than when the highest temperature was at the cantilever free end.