Abstract
A shear-force sensitive silicon sensor is developed using microfabrication technology. Four ion implanted piezoresistive resistors are embedded in a silicon diaphragm and used as independent strain gauges. An epoxy mesa is added on top of the diaphragm to transmit force from the load to the diaphgram. Both the shear and normal components of an applied force can be resolved by measuring the resistance variations of the four resistors. The sensor is tested when a 0-3 N variant force is applied at elevation angles of 0° (normal), 30°, 45° and 60°. At each elevation angle, the sensor rotates from 0° to 360° at an increment of 30°. Good linearity (R > 0.98) and high repeatability (standard deviation < 8 %) are observed. Both normal and shear sensitivities are measured. The shear sensitivity is characterized in terms of both magnitude and direction of the applied force. The results show that the sensor has a high sensing ability to both normal and shear forces (compared to commercial load cell). In this paper, the sensor design, fabrication and testing are described. The sensor characterization and shear sensing ability are discussed.
