Demonstration of β-Ga 2 O 3 MEMS resonators fabricated by crystallographic gas etching of (001) β-Ga 2 O 3 substrates

We report the first resonance characterization of β-Ga 2 O 3 -based doubly-clamped-beam resonators elongated along [100] and fabricated directly on a (001) β-Ga 2 O 3 substrate by crystallographic gas etching. The beams exhibited clear fundamental-mode resonances with quality factors ( Q ) on the order of 10 4 . Analysis of the beam-length dependence of the resonant frequency ( f 0 ) yielded an effective Young’s modulus of 143.2 (+16.4/−14.0) GPa within the Euler–Bernoulli beam approximation, while axial-stress analysis indicated only a small residual tensile stress. The f 0 Q values exceeded the highest reported values for transferred-flake-based doubly clamped beams, highlighting the potential advantage of crystallographic etching for fabricating β-Ga 2 O 3 microelectromechanical systems.