A Method for Fabricating CMOS Back-End-of-Line-Compatible Solid-State Nanopore Devices

TL;DR

This paper introduces a new low-temperature, CMOS-compatible fabrication method for solid-state nanopores, enabling integration with existing semiconductor processes for high-throughput molecular sensing.

Contribution

It develops and demonstrates BEOL-compatible deposition techniques for SiNx membranes, facilitating on-chip integration of nanopore sensors.

Findings

Successfully fabricated low-noise nanopores using new methods

Achieved single-molecule detection capabilities

Compatible with CMOS back-end-of-line processes

Abstract

Solid-state nanopores, nm-sized holes in thin, freestanding membranes, are powerful single-molecule sensors capable of interrogating a wide range of target analytes, from small molecules to large polymers. Interestingly, due to their high spatial resolution, nanopores can also identify tags on long polymers, making them an attractive option as the reading element for molecular information storage strategies. To fully leverage the compact and robust nature of solid-state nanopores, however, they will need to be packaged in a highly parallelized manner with on-chip electronic signal processing capabilities to rapidly and accurately handle the data generated. Additionally, the membrane itself must have specific physical, chemical, and electrical properties to ensure sufficient signal-to-noise ratios are achieved, with the traditional membrane material being SiNX . Unfortunately, the typical method of deposition, low-pressure vapour deposition, requires temperatures beyond the thermal budget of CMOS back-end-of-line integration processes, limiting the potential to generate an on-chip solution. To this end, we explore various lower-temperature deposition techniques that are BEOL-compatible to generate SiNx membranes for solid-state nanopore use, and successfully demonstrate the ability for these alternative methods to generate low-noise nanopores that are capable of performing single-molecule experiments.