Flexible Neural Electrode Arrays With Switch-Matrix Based on a Planar Silicon Process

Herein, we fabricate a flexible microelectronic system using a conventional silicon (Si) integrated circuit process. The fabricated device is a -thick film flexible 7 × 8 (56 ch) switch-matrix microelectrode array, which can be used to record the electrical activity from numerous three-dimensional biological tissues. The embedded Si-nMOSFETs/(111) in a polyimide flexible film exhibit a controlled threshed voltage with a leakage current of 10^-11 A and a subthreshold swing of 123 mV/decade at a 50-mV drain voltage. The electrical characteristics between the flat and bent (with a 3-mm curvature radius) devices do not significantly change in a saline environment. These results indicate that the proposed method, which does not utilize conventional transfer printing technology, may be used to fabricate high-performance flexible electronics via a high-resolution lithography process. Such flexible electrode arrays may be applicable to high spatial-resolution recordings of neuronal signals from three-dimensional tissues, such as the brain surface, retina, and peripheral nerves.