Resonance properties and microstructure of ultracompliant metallic nanoelectromechanical systems resonators synthesized from Al-32 at. % Mo amorphous-nanocrystalline metallic composites

Abstract

This study details the resonance properties of 20 nm thick nanoelectromechanical system scale cantilevers fabricated from a metallic Al-32 at. %Mo nanocomposite. The advantage of the Al-32 at. %Mo alloy is that its strength and near-atomic surface smoothness enable fabrication of single-anchored metallic cantilevers with extreme length-to-thickness ratios, as high as 400:1. This yields uniquely compliant structures with exquisite force sensitivity. For example, an 8 μm long, 20 nm thick Al-32 at. %Mo device has a spring constant of K280 μNm. We show through transmission electron microscope analysis and continuum modeling that the relevant damping mechanisms are related to the device microstructure.