Processing of novel SiC and group III-nitride based micro- and nanomechanical devices

Micromechanical 3C-SiC- and AlN-resonator beams with resonant frequencies between 20 kHz and 5 MHz have been realized. The 200 nm thin epitaxial SiC and group III-nitrides layers were grown on silicon (100) and (111) oriented substrates, respectively. Subsequent the beams were dry-etched by an electron cyclotron resonance (ECR) plasma technique. This new developed plasma based process allows anisotropic as well as isotropic etching for all materials involved. The created freestanding resonator bars have dimensions in the mu m to sub-mu m range. The operation principle based on a magneto motive actuation and a thin conductive metal layer on top of the resonator realizes the detection. We present a measurement setup for the electrical characterization of the bars and show coupled beams, to isolate the sensor signal from the excitation signal. Furthermore, we realized beams with a separate read-out unit (capacitive) as well as resonator structures with separate actuation (piezoelectric) to solve the problems of the superimposition of actuation and detection. (c) 2005 WILEY-VCH Verlag GmbH M Co. KGaA, Weinheim.