Transverse Vibration of Silicon Nanowires: Surface Properties

Abstract

Extreme miniaturization approaching single-digit nanometer linewidths is the outcome of the continuous need for increased performance and sensitivity. Silicon Nanowires (Si NWs) are promising building blocks with various applications in nanoelectromechanical systems. Despite notable advancements in fabrication and integration technologies, thorough characterization of NWs remains an ongoing process. Incorporating surface state with the native oxide and crystal anisotropy, recently introduced ExtZP model combines analytical and molecular dynamics approaches thereby providing a powerful, multiscale interpretation technique of quasistatic bending test results [1]. Simultaneously, transverse vibration is considered an ideal platform to study the surface effect on the size-dependent mechanical properties of Si NWs. A monolithic fabrication method is employed to fabricate Si NWs with nominal widths ranging from 10 nm to 80 nm. Their frequency response is assessed using base excitation and a laser doppler vibrometer (LDV MSA-600, Polytec GmbH). Surface properties (surface stresses and surface elastic constants) are then extracted through the ExtZP model and compared with available models for a detailed inspection of the role played by surface on transverse vibrational response of Si NWs.