We propose a microelectromechanical system (MEMS) nano-gap device capable of both gap formation and control on a single chip, designed for the experimental investigation of near-field thermal transport. Parallel plate nanogaps with large effective areas have high potential for applications such as thermal control devices. However, it is challenging to fabricate and control the nanogap with a less than 10 nm separation. Our previous approach using cleavage of silicon structure successfully solved this problem, but the external loading mechanism limits miniaturization and practical application. In this report, to address this limitation, we have designed and fabricated a device with an on-chip electrothermal actuator that applies load instead of an external mechanism. The actuator was designed using the finite element method (FEM) analysis that accurately takes into account the temperature-dependent physical properties of silicon. As a result, the displacement of the fabricated actuator was in-situ measured in a scanning electron microscope and showed good agreement with the FEM simulations. Although the gap fabrication by cleavage was not achieved due to an unexpected large curvature of the notch designed for cleavage initiation, this is a fabrication issue that can be solved by improving the photolithography process. This demonstrates the high feasibility of a single chip nanogap device without external mechanisms.
FUJIWARA et al. (Wed,) studied this question.