An Integrated-Circuit Approach to Extracellular Microelectrodes

TLDR

The authors present a multielectrode microprobe fabricated with integrated‑circuit techniques to address limitations of conventional microelectrodes. The probe comprises a gold electrode array on a silicon carrier, extending ~50 µm beyond the carrier, with a 0.4‑µm SiO₂ layer selectively etched at the tips by high‑resolution photoengraving to define recording sites, enabling arbitrary 2‑D array configurations. The fabrication permits interelectrode spacings of 10–20 µm or more and electrode‑tip diameters as small as 2 µm.

Abstract

This paper describes a new multielectrode microprobe which utilizes integrated-circuit fabrication techniques to overcome many of the problems associated with conventional microelectrodes. The probe structure consists of an array of gold electrodes which are supported on a silicon carrier and which project beyond the carrier for a distance of about 50 μ to allow a close approach to active neurons. These electrodes are covered with a thin (0.4-μ) layer of silicon dioxide which is selectively removed at the electrode tips using high-resolution photoengraving techniques to define the recording areas precisely. The processing sequence described permits any two-dimensional electrode array to be realized. Interelectrode spacings can be accurately controlled in the range from 10 to 20 μ or larger, and electrode-tip diameters can be as small as 2 μ.