Contactless Excitation of Acoustic Resonance in Insulating Wafers

TL;DR

This paper demonstrates a contactless method to excite and detect high harmonic acoustic resonances in insulating wafers using RF spectroscopy and magnetic fields, enabling precise measurements of elastic properties.

Contribution

It introduces a novel contactless excitation technique for acoustic resonances in insulators, applicable to samples with metallic surfaces, and provides high-resolution temperature-dependent elastic data.

Findings

Successful excitation and detection of acoustic overtones in silicon wafers.

Measured temperature dependence of sound velocity and elastic constants.

Method applicable to various samples with metallic surfaces.

Abstract

Contactless excitation and detection of high harmonic acoustic overtones in a thin insulator single crystal are described using radio frequency spectroscopy techniques. Single crystal [001] silicon wafer samples were investigated, one side covered with a Nb thin film, the common starting point for fabrication of quantum devices. The coupling between electromagnetic signals and mechanical oscillation is achieved from the Lorentz force generated by an external magnetic field. This method is suitable for any sample with a metallic surface or covered with a thin metal film. High resolution measurements of the temperature dependence of the sound velocity and elastic constants of silicon are reported and compared with known results.