GaN based piezo sensors

Abstract

This work presents a technology which has been developed to fabricate free-standing GaN membrane and cantilever structures. First experiments have enabled us to verify the piezo response of these GaN based cantilever structures. Especially, the bulk polarization doping generated in the base layer is a new important contribution. GaN heterostructures grown on 111-oriented Si wafers have been used. Free standing cantilevers and membranes have been fabricated using RIE and ICP dry etching. Cantilevers have been etched from the rear side or from the surface. It is expected that this technology will enable new device concepts based on stress induced pn-junction effects.