Fabrication of Surface Acoustic Wave Devices on Lithium Niobate

This article has been accepted and is currently in production

Abstract

Manipulation of fluids and particles by acoustic actuation on a small scale has spurred rapid development of lab-on-a-chip applications. Megahertz-order surface acoustic wave (SAW) devices generate enormous accelerations of up to 108 m/s2 on their surface. This is responsible for the effects that have come to define acoustofluidics: acoustic streaming and acoustic radiation forces. These effects have been used for particle, cell, and fluid handling at microscale and even nanoscale levels. In this paper we provide step-by-step descriptions of two major fabrication methods of SAW devices on lithium niobate: lift-off and wet etching. Representative results for the electrode pattern deposited on the substrate as well as the performance of SAW generated on the surface are provided in detail. Advice and troubleshooting for SAW production are covered as well. The aim is to provide the reader with a set of useful protocols for high frequency SAW device fabrication in future microfluidics applications.