Electrothermal tuning of Al-SiC nanomechanical resonators

A highly effective electrothermal tuning method is demonstrated for Al-SiC nanomechanical resonators. Doubly clamped beam devices are actuated and read out using a magnetomotive technique under a moderate vacuum at room temperature. Direct current applied to a beam heats the structure and shifts the resonance frequency downward. Frequency shifts of 10% are easily achievable, and the thermal time constant of these structures is in the submicrosecond range. The initial frequency and frequency tunability are studied for beams of varying Al thickness, and the device performance can be accurately modelled using simple mechanical and thermal models. Because of the different mechanical properties of SiC and Al, both the initial frequency and the frequency tunability can be modified by varying the Al layer thickness. This approach has the potential to become an important tool for effective frequency tuning in deployable SiC-based nanoelectromechanical system devices and systems for applications that would benefit from SiC as the structural material.