Silicon-based microelectrodes for neurophysiology, micromachined from silicon-on-insulator wafers

A process is described for the fabrication of silicon-based microelectrodes for neurophysiology using bonded and etched-back silicon-on-insulator (BESOI) wafers. The probe shapes are defined without high levels of boron doping in the silicon; this is considered as a step towards producing probes with active electronics integrated directly beneath the electrodes. Gold electrodes, of 4 microns by 4 microns to 50 microns by 50 microns are fabricated on shanks (cantilever beams) 6 microns thick and which taper to an area approximately 100 microns wide and 200 microns long, which are inserted into the tissue under investigation. The passive probes fabricated have been successfully employed to make acute recordings from locust peripheral nerve.