Silicon carbide (SiC) membrane nanomechanical resonators with multiple vibrational modes

We report on experimental demonstration of a new type of nanomechanical resonators based on very thin silicon carbide (SiC) square membranes. An optical interferometry with a radio-frequency two-port measurement scheme enables sensitive and efficient detection of many vibrational modes of the membranes. Membranes with sizes up to 1mm × 1mm and thicknesses down to t ≤ 500nm, offer very high aspect ratios and compelling resonance spectra of multiple-mode operations from kHz range to the HF (3-30MHz) band. Typical resonances have Q's ~ 800-30000 at room temperature and in vacuum of ~20mTorr. Some high-Q modes exhibit fairly strong nonlinear effects.