Current–voltage characteristics and breakdown of different structural planar microelectrodes in atmospheric air

With the development of applications for microelectromechanical system (MEMS) components and micromachining technology, planar microelectrodes have attracted considerable interest. To study the discharge characteristics of these structures, planar microelectrodes with a variety of plate-shaped and needle-shaped microelectrode structures fabricated from indium tin oxide (ITO) and copper (Cu) with microelectrode gaps ranging from 5 to 35 µm were manufactured using MEMS technology in this study. Experiments carried out in atmospheric air show that the microelectrode configuration has a crucial impact on the discharge current, breakdown voltage, and current response to varying electrode gaps. The electrode surface area plays a significant role in the discharge characteristics of planar microelectrodes, which is a factor dominating the discharge current and breakdown voltage. The commonly used formulas in macroscale corona discharge cannot be directly applied to planar microelectrodes. Planar microelectrodes fabricated with Cu on Si substrates have larger discharge currents, higher breakdown voltages, and better resistance to breakdown strength than ITO ones on quartz substrates under nA-scale current, while ITO damaged microelectrodes because of breakdown can still discharge when accompanied by different discharge characteristics.