Saw Pressure Sensor on Thin Lithium Niobate Using a Transfer of Separately Fabricated Cavities

A novel lithium niobate SAW pressure sensor is presented. A 50(+-10) μm thin lithium niobate layer is used as the sensor diaphragm. A glass slide with sand-blasted cavities is used as the substrate. SAW devices are fabricated on 500 μm lithium niobate substrates. Mechanical grinding and polishing are used to thin the lithium niobate SAW device. Subsequently, it is bonded to the glass substrate. In our process SAW devices are fabricated before the thinning and the transfer process. This leads to better device performance and good fabrication yield. The device shows a sensitivity of 347 Hz/KPa to pressure applied by a nitrogen gun.