Characterization of a highly sensitive silicon based three-axial piezoresistive force sensor

Recently, several three-axial silicon based force sensors have been developed. To mimic human mechanoreceptors and give sense of touch to robots highly integrated and highly sensitive three-axial force micro-sensors are required. We have fabricated silicon based 3D force sensors with piezoresistive gauges. In this paper we present a new method of electrical sensitivity characterization using an equipment normally dedicated for standard wire bonding applications such as wire pull or bonding´s shear. The measurements have been validated with a Nanoindenter and a good correlation is obtained with Finite Element Modeling (FEM). A sensitivity of 0.8mV/V/mN under normal forces is measured, one of the highest sensitivity value reported in the literature for piezoresistive 3D force sensors.