Fabrication of silicon nitride membrane nanoelectromechanical resonator

Abstract

In this work, we present details of the nanofabrication process for achieving a silicon nitride nanoelectromechanical resonator, consisting of a membrane covered with a thin aluminium layer capacitively coupled to a suspended top gate. Critical nanofabrication steps have been discussed, including the ${\mathrm{XeF}}_2$ selective etching process to release the silicon nitride membrane from the substrate and the reflow process to fabricate a top gate of a suspended membrane. This ultra-clean and CMOS-compatible process allows the silicon nitride membrane to have a high quality factor ($\sim$1.1$\times {10}^4$) at room temperature and offers access to electrical integration with external circuits with high efficiency. In addition, we also demonstrate parametric amplification and de-amplification of the input signals by exploiting this suspended top gate. The measurement results of phase-sensitive amplifications have also been well fit by analytical caculations. The present work provides essential building blocks for further exploration of silicon nitride membrane based nanoelectromechanical resonators that can be efficiently integrated into large-scale electrical circuits.