Authors: A.P. Friedrich, P.A. Besse, M. Bächtold and R.S. Popovic
Affilation: Swiss Federal Institute of Technology of Lausanne, Switzerland
Pages: 419 - 422
Keywords: piezo-tunnel effect, p-n junction, heavy doping, silicon strain sensor, microsystem
We present a new model of the piezo-tunnel effect in a heavily doped silicon p-n junction. Our approach is based on the coupling of a strain-dependent description of the energy exterma in the valence and conduction bands with the theory of indicrect tunneling developed by Kane. For any direction of stress and current flow, our model allows the calcuation of the current density as a function of the stress level, the bias voltage, the temperature and the doping concentrations at both sides of the junction. ALl silicon constants used in the numerical simulations are taken from literature, so that no fitting parameters have been used. The simulated tunneling current I, gauge factor K and temperature coefficients of carrent \alpha and of gauge factor \Beta are in fair agreeement with the experimental data measured on our integrated piezo-tunneling strain sensors.