The piezoelectric transistor (PET) - a novel paradigm in electronics

Energy consumption of electronics has been decreasing significantly over the past decades but it has now reached a fundamental limit called the Boltzmann Tyranny. Present technology achieves switching voltages of around 1V, but with increasing need for power and computation, we have to do better. Since the regular CMOS is limited by fundamental Physics, this problem calls for a change of paradigm. The Piezoelectric transistor (PET) is an innovative device that uses a piezoelectric mechanical actuator (PE) to switch the electronic conductivity of a piezo-resistive component (PR) between OFF and ON states. Voltage is applied on the PE which in turn induces stress in the PR. The latter changes its conductivity under applied stress and undergoes an insulator to metal transition. Thus the current flowing through PR is controlled by the gate voltage applied across the PE. When the device is turned ON the PR conductivity increases 4 orders of magnitude allowing current flow. The goal of this study is to find the optimal architecture that minimises the PE voltage required to turn the device ON. The conductivity of the PR is intimately related to the local stress. We performed finite element calculations to determine the stress distribution in the PR for various device geometries. Using results from ab initio computations we determined the conductivity dependence on the local stress. Combining these results, we solve the Continuity Equation assuming the differential form of Ohm's law. We found that the PET device can be switched with voltages around 200 mV!