Fabrication and electrochemical characterization of submicrometer interdigitated ultramicroelectrode arrays

A gold submicrometer interdigitated ultramicroelectrode array (IDA) was fabricated by conventional photolithographic patterning of multilayered materials. The IDA structure, which consists of 50 pairs of fingers and has 1.5 mm finger length and 362 nm functional band width, is fabricated in a small region (1.5 mm × 2.3 mm) on a quartz substrate. The electrode surfaces are inside the trenches. Gold film thickness is the electrode width that is exactly measured by atomic force microscopy (AFM). The surface topographies of gold film and substrate are characterized by AFM for the study of the variation of electrode width. Scanning electron microscopy (SEM) is used to visualize the quality of fabrication and to measure the fingers. Electrochemical properties of IDA electrodes are investigated by cyclic voltammetry through three-electrode system. It is shown that IDA electrodes can be used as the disposable ultramicroelectrodes of chemical and biologic sensors.