Atomic layer deposition (ALD) tungsten nano-electromechanical transistors

In this paper a relatively simple, CMOS compatible, top-down nano-fabrication process used in the fabrication of 3-terminal NEMS switches is introduced. The process is low-temperature, using atomic layer deposition tungsten (WALD) deposited at 120°C as the structural material. In addition, the unique use of electron beam lithography in conjunction with reactive ion etching (RIE) and lift-off techniques enable simple and reliable fabrication of n-terminal devices with up to n-different terminal/source gap heights. With this process, novel 3-terminal WALD NEMS switches analogous to NMOS transistors have been successfully fabricated, and switching behavior characterized. The devices are easily reproducible from chip-to-chip, have a much higher yield when compared to similar devices fabricated by bottom-up or top-down processes, and have demonstrated actuation voltages that are superior to thin-film (TF) or carbon nano-tube (CNT) based switches.