Improvement of electrical insulating properties for defective metal/epoxy resin interface in power modules by micro-plasma jet

Xi Zhu, Xiuhan Guan, Luyi Dai, Xinglei Cui, Jiajie Fan, Zhi Fang

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

High-voltage power modules inevitably face the critical problem of electric field distortion at triple-junction point (Cu/insulation substrate/potting material) and accidental introduction of unexpected micro-metal defects on insulation substrate, which damages electrical insulating properties and induces breakdown. In this study, a novel precise surface treatment method based on atmospheric pressure micro-plasma jet (μ-APPJ) is proposed for rejuvenating and improving electrical insulating properties of defective Cu/epoxy resin (EP) substrate in power modules. Results show that a typical μ-APPJ with a diameter of about 200 μm is developed to precisely treat the micro-level metal defect in Cu/EP interface, and a spherical-clustered Si-containing functional film (∼Si-O4) can be fabricated on EP substrate by optimized Ar/Hexamethyldisiloxane (HMDSO)/μ-APPJ, which significantly enhances the hydrophobicity of EP surface. Moreover, the plasma-assisted film deposition around μm-defect improves interface electrical properties of defective Cu/EP samples, evidenced by higher flashover voltages and suppressed partial discharge. Further analysis based on simulations reveals that the deposited typical film not only promotes charge mobility and creepage distance on EP, but also introduces additional trap levels that capture electrons and inhibit electric field around metal defects, thereby suppressing partial discharge failure and improving electrical insulating properties.

Original languageEnglish
Article number158064
JournalApplied Surface Science
Volume638
DOIs
StatePublished - 30 Nov 2023

Keywords

  • Defect inhibition
  • Electrical properties improvement
  • Metal/epoxy resin interface
  • Plasma jet
  • Precise treatment

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