Electrostatic Microelectromechanical Logic Devices Made by CMOS-compatible Surface Micromachining

We have developed new microelectromechanical logic gate devices using microelectromechanical systems (MEMS) technology based on gold electroplating on a silicon wafer. Each device comprises a single cantilever and two or more electrostatic drive electrodes with an ohmic contact-pad for electrical fan-out. The results are read out as a voltage through a pull-down or pull-up resistor. Although most electronic transistor logic gates are composed of four transistors or more, the device used in this work was made with a single cantilever that could be tailored as various types of logic gates such as NOT, NAND, exclusive NOR (XNOR), and exclusive OR (XOR). For this reason, the scheme of the developed device offers scalability by which to reduce its footprint even further. The microelectromechanical operation of the logic was demonstrated and confirmed experimentally. These devices have potential as stable logic-memory circuits that could be used in harsh environments, such as in high-altitude space applications. © 2020 The Institute of Electrical Engineers of Japan.