Multi-cantilever HEMT-based resonant sensor

In this paper resonant sensor based on micro-machined high-electron mobility transistor (HEMT) in which multiple suspended resonant cantilevers serve as floating gates is proposed and its analytical and lumped equivalent circuit models are developed. The proposed HEMT-based multi-cantilever resonant sensor enables electrostatic actuation and electrical readout. Mass absorption by a cantilever results in the change in its mechanical resonant frequency. Mechanical oscillations of such a cantilever excited electrically control the source-drain current. Thus, its resonant frequency shift can be detected as a frequency shift in the resonant peak of the source-drain current. Mechanical oscillations of each cantilever and electromechanical transducer are represented by relevant circuit components. The developed equivalent circuit of multi-cantilever resonant sensor was used to simulate its frequency response using Is-Spice software. The simulation reveals an enhanced source-drain current with a peak at a single frequency for the array of the identical cantilevers. In the case of multiple different cantilevers the simulated source-drain current reveals peaks at frequencies corresponding to mechanical resonances of the cantilevers, as expected.