Thermal IR detection with nanoelectromechanical silicon nitride trampoline resonators

TL;DR

This paper demonstrates silicon nitride nanoelectromechanical trampoline resonators as highly sensitive, fast, uncooled thermal IR detectors with enhanced responsivity and broad spectral absorption.

Contribution

The study introduces NEMS trampoline resonators with significantly improved responsivity and broadband IR absorption for thermal detection.

Findings

Responsivity increased by over two orders of magnitude.

Achieved NEP of 7 pW/√Hz and 4 ms response time.

Broadband absorption of 50% from 1μm to 25μm.

Abstract

Nanoelectromechanical (NEMS) resonators are promising uncooled thermal infrared (IR) detectors to overcome existing sensitivity limits. Here, we investigated nanoelectromechanical trampoline resonators made of silicon nitride (SiN) as thermal IR detectors. Trampolines have an enhanced responsivity of more than two orders of magnitude compared to state-of-the-art SiN drums. The characterized NEMS trampoline IR detectors yield a sensitivity in terms of noise equivalent power (NEP) of 7pW/$\sqrt{Hz}$ and a thermal response time as low as 4 ms. The detector area features an impedance-matched metal thin-film absorber with a spectrally flat absorption of 50% over the entire mid-IR spectral range from 1$\mu m$ to 25$\mu m$.