Toward Monolithically Integrated Hybrid CMOS-NEM Circuits

Nanoelectromechanical (NEM) switches offer the advantages of zero off-state leakage current, abrupt switching characteristics, nonvolatile (NV) operation, and relatively low on-state resistance as compared with CMOS transistors predominantly used for digital computing today. NEM switches can be implemented using metallic interconnect layers formed in the back-end-of-line (BEOL) steps of a standard CMOS IC manufacturing process, in order to enable compact implementation of hybrid CMOS-NEM circuits. In this article, a release-etch method is developed for realizing BEOL NV-NEM switches with leq100-nm contact gaps. A functional array of BEOL NV-NEM switches is used to implement a hybrid CMOS-NEM IC for data search applications. NV-NEM switch design optimization to minimize the programming voltage and accelerate switching speed is discussed. A scaled NV-NEM technology is projected to be advantageous for high-speed, low-power reconfigurable computing applications. This projection is validated with experimental data for a BEOL NV-NEM switch implemented with a conventional 16-nm CMOS IC manufacturing process.