Realization of a diamond based high density multi electrode array by means of deep ion beam lithography

TL;DR

This paper presents a novel deep ion beam lithography method to create high-density, multi-electrode arrays in diamond, enabling advanced biosensing applications with embedded graphitic microstructures.

Contribution

It introduces a combined DIBL and FIB fabrication process for embedding conductive microstructures in diamond for the first time.

Findings

Successfully fabricated a 16-electrode biosensor in diamond

Demonstrated high-density electrode integration within 20 um diameter

Enabled simultaneous amperometric recordings from neuroendocrine cells

Abstract

In the present work we report about a parallel-processing ion beam fabrication technique whereby high-density sub-superficial graphitic microstructures can be created in diamond. Ion beam implantation is an effective tool for the structural modification of diamond: in particular ion-damaged diamond can be converted into graphite, therefore obtaining an electrically conductive phase embedded in an optically transparent and highly insulating matrix. The proposed fabrication process consists in the combination of Deep Ion Beam Lithography (DIBL) and Focused Ion Beam (FIB) milling. FIB micromachining is employed to define micro-apertures in the contact masks consisting of thin (<10 um) deposited metal layers through which ions are implanted in the sample. A prototypical single-cell biosensor was realized with the above described technique. The biosensor has 16 independent electrodes converging inside a circular area of 20 um diameter (typical neuroendocrine cells size) for the simultaneous recording of amperometric signals.