CMOS microelectrode array for extracellular stimulation and recording of electrogenic cells

An extra cellular monolithic recording system fabricated in an industrial CMOS-technology combined with post-CMOS processing is presented. The chip comprises 16 platinum electrodes each equipped with stimulation and signal-conditioning circuitry. The micro-electrode array (MEA) is realized in a shifted-electrode design where the passivation is a 1.6 μm stack of alternating Si₃N₄ and SiO₂ required for effective chip protection. The electrode and its adjacent circuitry (which includes a stimulation buffer and a readout band-pass filter) form a modular unit that is repeated in a 4 by 4 structure. Simultaneous recording and stimulation is possible at all electrodes at any time throughout the measurement. The system architecture includes multiplexers and A/D converters for each row and a digital control unit that scans the array and provides a digital interface with the outside world.