Diamond - Application to piezoelectric bimorph cantilever sensors

Abstract

Micro-cantilevers are excellent tools to measure tiny forces (from 1 nN up to 10 N) as shown by the development of atomic force microscopy (AFM) techniques. That is the reason why micro-cantilevers are also the most sensitive acoustic sensors. For instance, one can use the variation of the cantilever's resonant frequency to measure mass loading. In this work, we will show first why diamond is the most suitable material for a special type of cantilever sensors: piezoelectric bimorph cantilever sensors. In contrast to other cantilevers, it is possible to actuate piezoelectric bimorph cantilevers and to detect their resonance frequencies simultaneously. Then, we present one application of this type of cantilever: a diamond/AlN cantilever used as a high pressure sensor (up to 7 ar). The sensor operates by monitoring the frequency shift of the first resonant mode (f 1 36.5 kHz). We have measured a sensitivity of 0.155 Hz/mbar in pure nitrogen