Simple technology for bulk accelerometer based on bond and etch back silicon on insulator wafers

A simple technology for bulk-micromachined accelerometers based on bond and etch back silicon on insulator (BESOI) wafers is presented. This technology is an easy combination of bulk- and surface-micromachining technology using the buried oxide as a sacrificial layer, allowing a precise control of the thickness of the beams and the fabrication of complex structures. Cantilever-beam, quad-beam, twin-mass [Chr. Burrer, J. Esteve, J.A. Plaza, M. Bao, O. Ruiz, J. Samitier, Fabrication and characterization of a twin-mass accelerometer, Sensors and Actuators A 43 (1994) 115-119] and a new triaxial accelerometer [J.A. Plaza, J. Esteve, E. Lora Tamayo, Acelerometro triaxial, Spanish Patent No. 9 701 154 (28 May, 1997) ] have been fabricated and their results are presented. Over-range structures have been included without any additional process step. The devices are anodically bonded to a glass wafer in order to reduce tie package stresses and to control the damping of the structures. (C) 1998 Elsevier Science S.A. All rights reserved.