A dual lateral-field-excited bulk acoustic wave sensor array

Recently, there has been interest in the fabrication of multiple quartz crystal microbalances (QCMs) on a single substrate to create a sensor array. However, such devices are ultimately subject to the limitations of the QCM configuration, requiring electrodes and wires on the sensing surface of the crystal substrate, resulting in a cumbersome arrangement that is unable to detect electrical property changes. The lateral-field-excited (LFE) sensor is a novel sensing device that only requires electrodes on the back side of the substrate. With a bare sensing surface, the LFE sensor is a better choice for implementing a sensor array. The purpose of this paper is to report on the fabrication and testing of two independent LFE devices on a single substrate. The individual LFE elements are shown to respond to both electrical and mechanical property changes, with minimal crosstalk between the LFE elements.