A new material concept for three-dimensional tactile piezoresistive force sensors

Abstract

The purpose of this paper is to present a new material concept to develop highly sensitive three-dimensional tactile force sensors. Conventional three-dimensional force sensors are based on silicon with integrated diffused silicon piezoresistors. Micromechanical force sensors using a soft material instead, e. g. SU-8 resist, would be more sensitive for static deflection measurements. As a characteristic factor for the sensitivity, the ratio of the gauge factor k to the Young's modulus E is presented for different sensor types. Beside silicon, especially gold, carbon black particles, and diamond-like carbon is taken into consideration as piezoresistive material. In addition four different SU-8 sensor prototypes are mechanically characterized with regard to their bending stiffness, probing forces at different deflections, and breaking points.