Simultaneous Capacitive and Electrothermal Position Sensing in a Micromachined Nanopositioner

This letter reports a micromachined nanopositioner with capacitive actuation together with capacitive and electrothermal sensing on a single chip. With the actuation voltage of 60 V, the electrostatic actuator can achieve a maximum displacement of 2.32 μm. The displacement can be simultaneously measured using capacitive and electrothermal sensors. Both sensors are calibrated to operate at a sensitivity of 0.0137 V/V. The electrothermal sensor is found to display 1/
f
noise, which affects the low-frequency measurements obtained from this device. However, at higher frequencies, it displays a lower noise power spectral density when compared with the capacitive sensor. The comparisons of frequency responses, power consumptions, and noise performances are presented in this letter.