Integration of a Carbon Nanotube Network on a Microelectromechanical Switch for Ultralong Contact Lifetime

Micro-/nanoelectromechanical (MEM/NEM) switches have been extensively studied to address the limitations of transistors, such as the increased standby power consumption and performance dependence on temperature and radiation. However, their lifetimes are limited owing to the degradation of the contact surfaces. Even though several materials and structural designs have been recently developed to improve the lifetime, the production of a microswitch that is compatible with a complementary metal-oxide semiconductor (CMOS) with a long lifetime remains a significant challenge. We demonstrate a vertically actuated MEM switch with extremely high reliability by integrating a carbon nanotube (CNT) network on a gold electrode as the contact material using a low-temperature, CMOS-compatible solution process. In addition to their outstanding mechanical and electrical properties of CNTs, their deformability dramatically increases the effective contact area of the switch, thus resulting in the extension of the lifetime. The CNT-coated MEM switch exhibits a lifetime that is more than 7 × 10⁸ cycles when operated in hot-switching conditions, which is 1.9 × 10⁴ times longer than that of a control device without CNTs. The switch also shows an excellent switching performance, including a low electrical resistance, high on/off ratio, and an extremely small off-state current.