Protruding Ceramic Substrates for High Voltage Packaging Of Wide Bandgap Semiconductors
Résumé
—Wide bandgap semiconductors enable high voltage (10 kV and more) switches. As a consequence, new packaging solutions are required to prepare the ground for such devices. The metallized ceramic substrate is a well-known and established technology for voltages up to 3.3kV, but it exhibits some weaknesses at higher voltages: due to its manufacturing process, the profile of the metallization is sharp and induces a reinforcement of the electric field at the " triple point " area (where the ceramic, the conductor and the encapsulating material meet), which can lead to Partial Discharges (PD), eventually causing a failure of the module. In this paper, we present a new substrate structure, where the triple point is moved away to an area where the electric field is lower. In this structure, the ceramic is machined to form protrusions, and round-edge metallizations are brazed on top. The design of the substrate, based on finite-elements is described, and calculations show that a 1 mm-thick AlN layer should be sufficient to withstand 10 kV. The manufacturing process of this substrate is presented. The test results demonstrate the superiority of this new solution, with a partial discharge inception voltage increased by 38 %.
Domaines
Energie électriqueOrigine | Fichiers produits par l'(les) auteur(s) |
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