A micro-fabricated planar high-current IrOx stimulating microelectrode

Describes the development and presents test results of a thin-film, high-current density, iridium oxide (IrOx) microelectrode for neuromuscular stimulation. The electrode is made of a silicon substrate with polysilicon lines as the interconnect and IrOx as the electrode material. The polysilicon lines are protected from body fluids by silicon dioxide and silicon nitride. The electrode is capable of injecting large amounts of charge (/spl sim/2 /spl mu/C) through a small area (/spl sim/0.3 mm/sup 2/), and can withstand more than 2 billion 10 mA, 200 /spl mu/sec, charge balanced current pulses in phosphate buffered saline (PBS) with minimal degradation in performance. IrOx is used as the electrode material because of its high charge injection capacity. These electrodes are fabricated using standard microelectronic fabrication technologies.