Microcantilever array with embedded metal oxide semiconductor field effect transistor actuators for deflection control, deflection sensing, and high frequency oscillation

Abstract

A batch fabricated microcantilever array with embedded metal oxide semiconductor field effect transistor (MOSFET) is demonstrated to behave as an actuator as well as a strain sensor. Actuation is made possible through MOSFET self-heating effect and metal-silicon bimaterial thermal expansion mismatch. Precise cantilever deflection is achieved with gate modulated saturation current. Controllable deflection and oscillation are demonstrated, with amplitude of 212 nm measured through laser interferometry near first resonant frequency. Higher amplitude is attainable through higher bias. Such in situ actuation and sensing promises to have applications ranging from nanolithography to microfluidic mixing, among others, which require precise and controllable nanoscale deflection.

Cantilever-free thermal actuation

“…1,2 In particular, the ability to micromachine silicon at the wafer scale has been an enabling technology for scanning probe-based techniques wherein nanoscale tips are fabricated on passive 3,4 and selfactuating [5][6][7][8] cantilevers. 1,2 In particular, the ability to micromachine silicon at the wafer scale has been an enabling technology for scanning probe-based techniques wherein nanoscale tips are fabricated on passive 3,4 and selfactuating [5][6][7][8] cantilevers.…”

Self-driving capacitive cantilevers for high-frequency atomic force microscopy

“…10 Actuators have also been fabricated onto cantilevers to drive them directly, such as piezoelectrics, 11 Schottky diodes 12 and transistors. 13 Capacitors with air 14,15 and dielectric 16 gaps integrated with AFM cantilevers have previously been used to drive and sense deflections of cantilevers with low (≤ 60 kHz for air gaps and ~ 2 kHz for dielectric gaps) resonance frequencies.…”