A microaccelerometer structure fabricated in silicon-on-insulator using a focused ion beam process

Abstract Focused ion beam processing (FIB) has been employed for the fabrication of a microaccelerometer structure starting with bonded silicon-on-insulator substrates. A short FIB processing step involves cutting a narrow gap obliquely in a silicon beam. This gap is used for reading out an acceleration. The process time is less than 2 min which could be viable for the manufacture of high value sensors. SOI material is ideal to fabricate suspended structures with simple processing steps. A novel, so-called `tapping mode' readout is studied. It is based on a periodic closing of the readout gap and a duty cycle measurement. Electron tunnelling readout is proposed for high sensitivity applications.

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