Development and characterization of a needle-type microelectrode array for stimulation and recording of neuronal activity

Development and characterization of a needle-type microelectrode array for stimulation and recording of neuronal activity
Roehler S, Held J, Nisch W. Kern DP, Burkhardt C, Stett A
Microelectronic Engineering. 2012 Oct; 98:453-457. doi: 10.1016/j.mee.2012.07.104

Arrays of needle-type electrodes are expected to surpass arrays of planar electrodes used for measuring neuronal activity or stimulation of neurons concerning properties like stimulation threshold, spatial resolution and signal-to-noise ratio. This work describes the fabrication of such needle-type electrodes. The three-dimensionally shaped electrodes are 50 µm high. Typical values for the base diameter are 20 µm and a few microns for the tip radius. The needles are fabricated from cross-linked SU-8 using dry etching. Gold and titanium are used as metallization and SiOxCy as insulator. The tips of the electrodes are covered with nano-columnar titanium nitride.