Precise Surface Modification of Insulating Materials by Nanosecond Pulse Excited Micro-Plasma Jets

With the widespread use of high-voltage and high-power power electronic devices with wide-bandgap materials, the insulating properties of their packaging have gradually become a research hotspot. Currently, the packaging insulation is mainly improved by means of geometric structure design, dielectric constant regulating and material modification. However, the solid-solid micro-interface existed in packaging structure causes electric field concentration and partial discharge, eventually leading to the breakdown of insulation. A precise and reliable processing is required for the micro-interface without damaging other devices to improve the reliability of the insulation. In this paper, an atmospheric pressure micro-plasma jet driven by nanosecond pulsed power was established, and siloxane precursor was introduced to form the enhanced film at the interface between the insulating layer and the metal. The results show that the width of plasma plume is controlled to hundreds of microns and the length is about tens of millimeters, which fully meets the need for the precise modification. Furthermore, the micro-treated-area on resin surface shows good hydrophobicity and electrical insulating properties, which contributes to the application of micro-plasma jets in precise surface modification.