The device processing for the double-clamped GaN bridge resonator on Si substrate:
(1) The as-grown GaN epitaxial film on Si substrate. Except for the AlN buffer layer, no strain removal layer is used.
(2) Spin coating of the photoresist on the GaN-on-Si sample.
(3) Laser lithography to define the pattern for the double clamped bridge configuration.
(4) Plasma etching to remove the GaN layer without photoresist.
(5) Chemical etching to release Si under the GaN layer. Therefore, the air gap is formed.
(6) The final device structure of the double clamped bridge resonator. We use the laser doppler method to measure the frequency shift and resolution under different temperatures.