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 (BES OI) wafers. The probe shapes are defined without high levels of boron dopin g in the silicon; this is considered as a step towards producing probes wit h active electronics integrated directly beneath the electrodes. Gold elect rodes, of 4 mu m by 4 mu m to 50 mu m by 50 mu m are fabricated on shanks ( cantilever beams) 6 mu m thick and which taper to an area approximately 100 mu m wide and 200 mu m long, which are inserted into the tissue under inve stigation, The passive probes fabricated have been successfully employed to make acute recordings from locust peripheral nerve.