A silicon-based shear force sensor: development and characterization

A silicon-based sheer force sensitive sensor is developed using microfabrication technology. Four ion-implanted piezoresistors are embedded in a silicon diaphragm and used as independent strain gauges. An epoxy mesa is built-up on top of the diaphragm to convert an applied force to a distributed stress. Both the normal and the shear components of an applied force can be resolved from the resistance changes induced by the stress, The sensor is tested when with a 0-3 N variant force is applied at elevation angles of 0 degrees, 30 degrees, 45 degrees and 60 degrees. At each elevation angle, the sensor is rotated from 0 degrees to 360 degrees at increments of 30 degrees. Good Linearity (R approximate to 0.98) and good repeatability (STD approximate to 3%) are observed. A sensor model is established in order to investigate the shear sensing ability and force measurement mechanism. The experimental results are in good agreement with the sensor model. Shear force sensing ability is demonstrated. In this paper, the sensor's design, fabrication and characterization are described. Based on the experimental data and the model, the sensor's shear sensitivity is discussed in detail. (C) 2000 Elsevier Science S.A. All rights reserved.