Graded Dielectric Insulation for High Power Density Semiconductors
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Solution Overview
Problem
High voltage and high power density applications in semiconductor devices and busbars face challenges due to partial discharge and creeping discharges, which reduce insulation reliability and power converter efficiency, primarily due to inadequate electrical insulation capabilities, especially in wide-bandgap devices.
Innovation Solution
The implementation of an electrophoretic deposition method for creating insulation systems with composite coatings that have a varying dielectric constant, using particles dispersed in a polymer matrix, which reduces electric field stress and enhances thermal conductivity, allowing for capacitive grading and improved insulation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher power switching devices (SiC and GaN) are used to increase power density, then power density increases, but partial discharge and creeping discharges occur due to high electric fields, reducing insulation reliability
Solution Approach 1:
The patent applies local quality by creating a graded insulation system where the dielectric constant varies spatially. The insulation system includes multiple layers with different dielectric constants, with higher dielectric constant materials positioned closer to the semiconductor device where electric field stress is highest, and lower dielectric constant materials positioned farther away. This gradient structure locally optimizes the insulation properties at each position to handle the varying electric field intensity, thereby preventing partial discharge and creeping discharges while enabling high power density operation.
Solution Approach 2:
The patent employs composite materials by combining multiple dielectric materials with different properties into a single insulation system. The system integrates materials with varying dielectric constants, thermal conductivities, and mechanical properties to create a multi-layered insulation structure. This composite approach allows the insulation system to simultaneously provide electrical insulation, thermal management, and mechanical support, resolving the contradiction between high power density and insulation reliability.
2Reliability
If insulation thickness is increased to prevent discharge, then insulation reliability improves, but device size increases, reducing power density
Solution Approach 1:
The patent uses local quality to optimize insulation thickness distribution. Instead of uniform thick insulation throughout, the system places thicker insulation layers with higher dielectric constants only in regions experiencing high electric field stress (near the semiconductor device and conductive components), while using thinner layers with lower dielectric constants in regions with lower stress. This localized approach achieves adequate insulation reliability while minimizing overall device volume and maintaining high power density.
3Temperature
If ceramic materials with high thermal conductivity are used, then thermal management improves, but dielectric constant is too high, increasing electric field stress and causing discharge
Solution Approach 1:
The patent applies local quality by strategically positioning materials with high thermal conductivity but moderate dielectric constant in regions where thermal management is critical (such as near heat-generating components), while using materials with lower dielectric constants in regions where electric field stress is highest. This spatial differentiation allows the system to simultaneously achieve effective thermal management and electrical insulation, resolving the contradiction between thermal conductivity and insulation reliability.
Solution Approach 2:
The patent employs composite materials by creating a multi-material insulation system that combines ceramics with different thermal and dielectric properties. The system integrates materials optimized for thermal conduction with materials optimized for electrical insulation, arranging them in a graded structure where each material's properties are leveraged in the appropriate location. This composite approach enables the insulation system to provide both thermal management and electrical protection, resolving the contradiction between thermal conductivity and insulation reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces electrical discharges, increases insulation reliability, and enables higher power density converters with improved thermal management and capacitive coupling, addressing the limitations of existing insulation systems in high voltage and high power applications.
Implementation Method 1
disposing an insulation system on a least a portion of a surface of the semiconductor device, the conductive component, and the substrate, via an electrophoretic process
Data Source
AI summary
This present disclosure generally relates to systems and methods of electrophoretic deposition (EPD) techniques for use in insulation systems at least partially encapsulating a semiconductor device, a conductive component and a substrate, such as insulation systems of semiconductor devices, busbars, or the like. Insulation systems formed using EPD processes may be designed to have a dielectric constant that decreases in a direction away from a substrate of the insulation system. This may improve insulation technologies since depositing coatings with sequentially arranged dielectric constants may improve resistance of the insulation system to high temperature, high electric fields, or the like.