A Flexible a-SiC-Based Neural Interface Utilizing Pyrolyzed-Photoresist Film (C) Active Sites

Area of Science:

• Materials Science
• Biomedical Engineering
• Neuroscience

Background:

• Carbon materials like graphene and carbon-nanotubes (CNT) are promising for neural interfaces due to conductivity.
• Current fabrication methods for carbon electrodes face challenges in large-scale production and repeatability.
• Developing robust and repeatable fabrication processes is crucial for advancing implantable neural interfaces.

Purpose of the Study:

• To demonstrate a repeatable fabrication process for neural interface electrodes using pyrolyzed-photoresist-film (PPF) and amorphous silicon carbide (a-SiC).
• To simplify electrode fabrication by eliminating noble metal processes.
• To evaluate the electrochemical performance of PPF electrodes.

Main Methods:

• Fabrication of carbon electrodes and traces using pyrolyzed-photoresist-film (PPF) directly on amorphous silicon carbide (a-SiC) insulation.
• Utilizing standard semiconductor fabrication tools for repeatable processes.
• Electrochemical characterization of PPF electrodes in oxygenated phosphate buffered solution (pH 7.4).

Main Results:

• Achieved excellent electrochemical charge storage capacity (CSC) of 14.16 C/cm².
• Demonstrated low impedance of 24.8 ± 0.4 kΩ at 1 kHz.
• Obtained a phase angle of -35.9 ± 0.6° at 1 kHz for a 1.9 kµm² recording site area.

Conclusions:

• PPF combined with a-SiC provides a simplified and repeatable fabrication route for neural interface electrodes.
• The developed method eliminates complex noble metal deposition and lift-off steps.
• PPF electrodes exhibit promising electrochemical properties for neural recording applications.