High Voltage Limits for Electrostatic Transducers: on the Role of Ambient Pressure and Device Dimension in Microdischarges

In order to understand the details of high-field breakdown in microstructures that are vacuum packaged, a series of experiments are used to determine characteristics of microdischarges. It is found that many of these contradict conventional assumptions based upon large scale discharges. When planar microelectrodes are used, Paschen’s curve is not followed; the anode and cathode current paths are a strong function of pressure; voltage gradients are supported in the glow region; and the glow region is confined directly over the cathode. It is shown that magnets can be used to further confine the discharge. This information is pertinent for recently reported devices that exploit microdischarges for sensing.