Microcantilever actuation via periodic internal heating

This paper reports electrothermal actuation of silicon microcantilevers having integrated resistive heaters. Periodic electrical excitation induced periodic resistive heating in the cantilever, while the cantilever deflection was monitored with a photodetector. Excitation was either at the cantilever resonant frequency, $f0$⁠, $f0∕2$⁠, or $f0∕3$⁠. When the time averaged maximum cantilever temperature was $174°C$⁠, the cantilever out-of-plane actuation amplitude was $484nm$ near the cantilever resonance frequency of $24.9kHz$⁠. This actuation was sufficiently large to operate the cantilever in intermittent contact mode and scan a calibration grating of height of $20nm$⁠.