We present the fabrication of highly P-doped single crystal silicon electrodes on a silicon probe through complementary metal-oxide-semiconductor (CMOS)-compatible processes. The electrode with diameter of 50 lm and a separation of 200 lm is designed for recording/stimulating purposes. Electrochemical impedance spectroscopy indicates that the interfacial impedance of silicon electrodes at 1 KHz is 2.560.4 MX, which is equivalent to the result reported from the gold (Au) electrode. To further enhance the charge storage capacity, composites of multi-wall carbon nanotubes (MWCNTs) and Au nanoparticles are electroplated onto the highly P-doped silicon electrode after surface roughness treatments. With optimized electroplating processes, MWCNTs and Au nanoparticles are selectively coated onto the electrode site with only a minimum enlargement in physical diameter of electrode (<10%). However, the typical impedance is reduced to 2163kX. Such improvement can be explained by a boost in double-layer capacitance (Cdl) and the reduction in faradic resistances. The measurement of cyclic voltammetry (CV) shows that the cathodal charge storage capacity is up to 35 mC cm 2, which proves the superior performance of composite coatings
on silicon electrodes and validates the functionality of reported CMOS-compatible silicon probe.