# Wafer-Scale All-Dielectric Quasi-BIC Metasurfaces: Bridging High-Throughput Deep-UV Lithography with Nanophotonic Applications

## TL;DR

This paper introduces a scalable method to fabricate high-performance nanophotonic metasurfaces using deep-UV lithography, enabling practical applications in biosensing and photonic systems.

## Contribution

A wafer-scale fabrication technique for quasi-BIC metasurfaces using DUVL, overcoming resolution limits and enabling CMOS-compatible sensing.

## Key findings

- qBIC resonances with Q-factors of 150 were achieved using DUVL-fabricated silicon nitride hole arrays.
- Spatial uniformity was maintained despite nanoscale variations due to the nonlocal nature of qBIC resonances.
- Refractive index sensing achieved 129 nm/RIU sensitivity using CMOS camera-based interrogation.

## Abstract

High quality-factor
(Q) dielectric metasurfaces operating
in the
visible to near-infrared range require sub-200 nm features, limiting
fabrication to expensive, low-throughput electron beam lithography.
Here, we demonstrate wafer-scale metasurfaces fabricated using deep
ultraviolet lithography (DUVL), a workhorse technology in the semiconductor
industry. Using a radius and depth perturbation technique in a hole
array patterned into a silicon nitride slab, we achieve quasi-bound
states in the continuum (qBIC) resonances with measured Q-factors
of 150. We introduce DUV exposure dose as a Q-factor engineering parameter
and demonstrate how hole depth control circumvents DUVL resolution
limits. Despite stochastic nanoscale variations, the fabricated metasurfaces
exhibit spatial uniformity, a consequence of the nonlocal nature of
the qBIC resonances. Refractive index sensing demonstrates 129 nm/RIU
sensitivity while maintaining CMOS camera-based resonance shift interrogation.
This work bridges scalable semiconductor manufacturing with high-performance
nanophotonics, establishing a practical pathway for commercializing
metasurface-based biosensors, on-chip spectrometers, and integrated
photonic systems.