Back-end-of-line compatible Poly-SiGe lateral nanoelectromechanical relays with multi-level interconnect

Nanoelectromechanical (NEM) relays show promise in a wide variety of low power applications. NEM relays have near-zero leakage current, in contrast to the relatively high leakage current of nanoscale CMOS transistors, thus enabling hybrid CMOS-NEM relay systems that are more energy efficient. If NEM relays can be fabricated in the back-end-of-line (BEOL) metallization process, they can be added to a CMOS integrated circuit without adding significantly to the die area. In this paper, we demonstrate a CMOS BEOL-compatible fabrication process of NEM relays with protected, buried interconnects. The NEM relay processing steps are at temperatures below 425 A degrees C and all mechanical and chemical processing steps are designed to avoid damage to underlying CMOS transistors. We demonstrate a lateral relay with buried interconnect that switches for more than 1000 cycles with resistances below 300 k Omega in nitrogen at atmospheric pressure.