Wafer-Scale Fabrication of Uniform, Micrometer-Sized, Triangular Membranes on Sapphire for High-Speed Protein Sensing in a Nanopore

Abstract

Ultra-low-noise solid-state nanopores are attractive for high-accuracy single-molecule sensing. A conventional silicon platform introduces acute capacitive noise to the system, which seriously limits the recording bandwidth. Recently, we have demonstrated the creation of thin triangular membranes on an insulating crystal sapphire wafer to eliminate the parasitic device capacitance. Uniquely different from the previous triangular etching window designs, here hexagonal windows were explored to produce triangular membranes by aligning to the sapphire crystal within a large tolerance of alignment angles (10–35°). Interestingly, sapphire facet competition serves to suppress the formation of more complex polygons but creates stable triangular membranes with their area insensitive to the facet alignment. Accordingly, a new strategy was successfully established on a 2 in. sapphire wafer to produce chips with an average membrane side length of 4.7 μm, an area of <30 μm2 for 81% chips, or estimated calculated membrane capacitance as low as 0.06 pF. We finally demonstrated <4 μs high-speed and high-fidelity low-noise protein detection under 250 kHz high bandwidth.

Iontronic Sensing Based on Confined Ion Transport

“…Renowned for their robustness and stability, these silicon-based nanopores excel in applications like DNA sequencing and single-molecule sensing. Various techniques, including high-intensity focused ion or electron beam (FIB/FEB) irradiations, − controlled dielectric breakdown (CDB), − electron beam lithography (EBL), and feedback controlled wet etching, , can be employed to drill or fabricate nanopores in membranes of silicon materials. These diverse techniques enable the development of reliable and high-performance silicon-based nanopores for various iontronic sensing applications.…”

“…Furthermore, the copper metal node introduced hydrophilic regions, minimizing nonspecific adsorption of DNA with the membrane. Ultimately, leveraging the Cu-TCPP MOF nanopore and its resulting prolonged dwell time enabled discrimination between poly(dA) 30 and poly(dC) 30 translocations. 217 Xing et al also showcased a comparable method for examining the translocation behavior of DNA homopolymers with varying lengths and bases.…”