CMOS integrated cantilevers with sub-μm tips for thermal sensing

This work presents the CMOS micromachined dielectric cantilevers with integrated sharp tips for surface temperature measurement. The integrated cantilever can perform electrothermal actuation and piezoresistive sensing for maintaining a proper tip-sample contact. For the cantilever of 280-mum long, the measured thermoelectric power from the aluminum/polysilicon thermocouple is 22.6plusmn0.36 muV/degC, the measured time constant is 796 mus, and the drift due to thermal actuation is 0.15plusmn0.057 muV/degC. The measured displacement by thermal actuation is 2.2 mum at 17.8 mW and the measured thermal time constant is 79.6 mus. The measured piezoresistive sensitivity and pre-amp noise are 0.48 mV/mum and 0.7 muV/Hz^1/2, respectively, producing an equivalent input-referred noise displacement of 1.45 nm/Hz^1/2.