Pre-breakdown Arcing and Electrostatic Discharge in Dielectrics under High DC Electric Field Stress

Highly disordered insulating materials exposed to high electric fields will, over time, degrade and fail, potentially causing catastrophic damage to devices. Step-up electrostatic discharge (ESD) tests were performed for two common polymer dielectrics, low density polyethylene and polyimide. Pre-breakdown transient current spikes or pre-arcs were observed, using both slow and high speed detection. These pre-ESD discharge phenomena are explained in terms of breakdown modes and defect generation on a microscopic scale. The field at which pre-breakdown arcing begins was compared to the onset field for electrostatic discharge at which complete breakdown begins to occur for each material. We present evidence that these two threshold fields are closely correlated. Thus, important considerations from applications of fields below the maximum field for breakdown may include the material's defect structure and the field where pre-breakdown arcing begins in a material.