In this paper we analyse a new type of silicon strain sensor based on the piezo- tunneling effect in a silicon lateral backward diode. The implantation profiles of the junction have been optimised to obtain a prevailing tunneling current at the reverse biased operating point. The optimisation was performed using a two- dimensional simulation of the fabrication process. The simulated profiles have been used for the numerical determination of the current flow in the structure. The experimental results clearly show that the tunneling current is dominant in the optimised devices. Finally, an analytical model of the tunneling current in a highly doped p-n junction is discussed.