A Ferroelectric CMOS Microelectrode Array with ZrO2 Recording and Stimulation Sites for In-Vitro Neural Interfacing

A CMOS-based microelectrode array (CMOS-MEA) is presented, where a 10-nm-thick antiferroelectric ZrO 2 layer is deposited in the post-CMOS process as functional electrode coating for 4225 recording sites and 1024 stimulation sites. Voltage noise measurements of the ZrO 2 recording sites of the CMOS-...

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Bibliographic Details
Published in:2024 IEEE BioSensors Conference (BioSensors) pp. 1 - 4
Main Authors: Becker, Maximilian T., Corna, Andrea, Xu, Bohan, Schroeder, Uwe, Amft, Oliver, Keil, Stefan, Thewes, Roland, Zeck, Gunther
Format: Conference Proceeding
Language:English
Published: IEEE 28.07.2024
Subjects:
Biosensors
Charge injection capacity
CMOS-based Microelectrode Array
Electric potential
Ferroelectric Microelectrodes
Microelectrodes
Noise level
Noise measurement
Optimization
Recording
Retina
Tin
Voltage measurement
Voltage noise
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Summary:A CMOS-based microelectrode array (CMOS-MEA) is presented, where a 10-nm-thick antiferroelectric ZrO 2 layer is deposited in the post-CMOS process as functional electrode coating for 4225 recording sites and 1024 stimulation sites. Voltage noise measurements of the ZrO 2 recording sites of the CMOS-MEA show reduced noise levels as compared to the same CMOS-MEA with uncoated TiN electrodes. Moreover, neural recordings of spontaneous activity of retinal ganglion cells reveal full functionality and biocompatibility of the insulating ZrO 2 interface material. The stimulation current of the ZrO 2 ferroelectric microelectrodes is investigated by applying triangular voltage signals to the stimulation sites of the CMOS-MEA. Up to voltage amplitudes of 3.2 V, the stimulation current consists of displacement current only, electrochemical (Faradaic) DC currents are suppressed. For voltage amplitudes above ~2.2 V, we observe a voltage-dependent increase in the stimulation current which we attribute to the ferroelectric properties of the ZrO 2 insulated microelectrodes. However, the enhancement of the charge injection capacity (CIC) of the insulated microelectrodes is below the full potential of antiferroelectric ZrO 2 and requires further optimization. Nevertheless, our results demonstrate the potential of ferroelectric CMOS-MEAs for safe and efficient neural recording and stimulation.
DOI:10.1109/BioSensors61405.2024.10712692