Subnanometer Positioning and Drift Compensation With Tunneling Current

This paper introduces tunneling current as a sensor to detect and control the displacements of micro- and nanoelectromechanical systems. Because of its extremely small magnitude, the tunneling current cannot be used without an appropriate control strategy. A control methodology involving two feedback loops is proposed to control displacements with an accuracy of 40 pm while also compensating the sensor drift. With this strategy, controlling displacements with an amplitude is possible, extending the predicted capabilities of tunneling current by the literature. The overall approach is a solution for the control of macro to nano systems and may be embedded in positioning applications requiring a very high degree of accuracy.