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

Focused ion beam processing (FIB) has been employed for the fabrication of a microaccelerometer structure starting with bonded silicon-on-insulator su bstrates. A short FIB processing step involves cutting a narrow gap oblique ly 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 structu res 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 dut y cycle measurement. Electron tunnelling readout is proposed for high sensi tivity applications. (C) 1999 Elsevier Science S.A. All rights reserved.