Group III-nitride and SiC based micro- and nanoelectromechanical resonators for sensor applications

Micro- and nanomechanical AlN and 3C-SiC resonator beams with resonant frequencies between 20 kHz and 2 MHz, depending on the resonator geometry, have been realized and characterized at ambient conditions. Up to 200 nm thin epitaxial group Ill-nitrides and SiC layers were grown on silicon (I 11) and (100) oriented substrates, respectively. The beams were dry-etched by an electron cyclotron resonance (ECR) plasma and an inductive coupled plasma (ICP) technique. The freestanding resonator bars have dimensions in the sub-mu m to nm-range. The operation principle based on the known magneto motive actuation and a thin conductive metal layer on top of the resonator realizes the detection. The main fabrication steps of the resonator beams are presented. The resonant frequencies, the quality factors of the MEMS and NTEMS are investigated in dependence on the geometry and the residual strain in the epitaxial layers. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.