High-throughput resonance testing: a characterization tool to study nanowire mechanics

Abstract

High-throughput (HTP) resonance testing is introduced as a mechanical characterization technique for nanowire arrays. As the demonstration platform, arrays of double-clamped silicon nanowires are employed with piezoelectric base excitation and optical detection through laser Doppler vibrometry. As multiple resonance modes of each nanowire can be measured in a single test run, this rapid and non-destructive characterization significantly increases testing throughput, thereby generating large datasets necessary for the statistical treatment of nanomechanical behavior. Its capabilities are demonstrated on the first three resonance modes of an array of eighteen silicon nanowires at frequencies up to 19 MHz, revealing sample-to-sample variations of up to five percent. Capturing this variability is critical, as it arises primarily from fabrication-induced dimensional deviations and intrinsic stresses. The latter is examined in greater detail to demonstrate the capabilities of the proposed characterization tool through a comparative study with Raman spectroscopy. HTP resonance testing enables consistent resolution of stress-induced mechanical changes across nanowire arrays, reducing uncertainty associated with stress-shift-coefficient dispersion from tens of MPa to uniquely resolved stress-change values for individual nanowires. Total measurement time is also reduced by a factor of three compared to single sample testing—a metric that will further improve with increasing nanowire array density. Consequently, supporting large datasets with mode-specific trend analysis and outlier identification, the technique strengthens the experimental foundation for reliable integration of nanowires into next-generation micro- and nanoelectromechanical technologies.