Semiconductor pressure sensor for extreme conditions
We introduced prototypes of semiconductor MEMS piezoelectric pressure sensors applicable at extreme conditions of high temperatures and chemically aggressive ambients. The sensing part of the MEMS sensor consists of a 2-4 µm thick circular AlGaN/GaN membrane with integrated circular high electron mobility transistors on its surface. The sensing electrodes are optimally situated at locations with maximal changes of mechanic strain as a consequence of external pressure loading. The pressure sensor works on originally proposed piezoelectric sensing principle based on the accumulation of induced charge on the sensing gate electrodes of the HEMT device by membrane deflection. The introduced MEMS pressure sensor represents the new generation of sensors exploitable for pressure measurements in harsh environments and induced by hydrodynamic or acoustic activation as well as acceleration (pressure measurements in combustion engines and on wings of aircrafts, etc.).
3D view of the MEMS pressure sensor and cross section with illustrated sensing electrodes.
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