SAW pressure sensor based on single-crystal quartz layer transferred on Silicon

In this paper, we present a wafer level approach to fabricate SAW pressure sensors on a single crystal AT-cut Quartz film transferred onto a bulk Silicon substrate. The final thickness of the quartz active layer was obtained using a combination of coarse mechanical thinning and fine polishing. Isolated Quartz membranes with a controlled thickness were then released by DRIE of the Silicon substrate. Details of the sensor fabrication process, modeling and electrical measurements are presented. In addition, theoretical considerations in good agreement with experimental results are disclosed.