GaAs based on bulk acoustic wave sensor for biological molecules detection

This paper investigates a high sensitive piezoelectric sensor in Gallium Arsenide (GaAs) crystal for biological molecules detection in liquid environment. The lateral field excitation was used to generate bulk acoustic waves (BAW) through (001) GaAs membranes. The crystallographic plane and the electric field orientation were chosen to obtain the highest electromechanical coupling coefficient for shear waves. Gallium Arsenide presents interesting alternative to quartz crystal concerning resonant biosensors thanks to its piezoelectric, acoustic properties, its ability to be directly bio functionalized and its common micro-fabrication processes. This offers an opportunity to combine a highly sensitive transducer fabricated using a batch process with a specific bio-interface which constitutes two essential parts of a biosensor. Analytical calculations and 3D finite element method (3D-FEM) analysis using Comsol Multiphysics r software were carried out to determine static, modal and vibration behaviors of the GaAs membrane. Typical numerical simulations and experimental results of the transducer in air were presented and discussed. The experimental results of GaAs-BAW in liquid for biological detection are also given in this study. (C) 2015 The Authors. Published by Elsevier Ltd.