SiC Semiconductor Device Curved Insulating Structure
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving high breakdown voltage while maintaining low on-resistance, primarily due to electric field concentration issues at the insulating portion's corners and bottom regions.
Innovation Solution
The semiconductor device incorporates a silicon carbide semiconductor portion with specific conductivity type regions and an insulating portion with tailored curvature radii and impurity concentrations, including a p-type region below the gate and strategically positioned insulating portions to relax electric field concentration and optimize current path characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the insulating portion has sharp corners or flat surfaces, then the manufacturing process is simpler, but electric field concentration occurs at corners and bottom regions reducing breakdown voltage
Solution Approach 1:
The insulating portion is designed with curved surfaces instead of flat surfaces or sharp corners. Specifically, the insulating portion has a first curvature radius R1 at its bottom surface and a second curvature radius R2 at its side surface, with R1 > R2. This curvature design eliminates electric field concentration at corners and bottom regions, thereby increasing breakdown voltage while maintaining manufacturing feasibility through standard semiconductor processing techniques.
2Manufacturing precision
If the insulating portion thickness is increased to reduce electric field intensity, then breakdown voltage increases, but on-resistance increases due to longer current path
Solution Approach 1:
The insulating portion employs different curvature radii at different locations: a larger first curvature radius R1 at the bottom surface facing the drift region, and a smaller second curvature radius R2 at the side surface. This local differentiation optimizes electric field distribution - the larger R1 reduces electric field intensity at the critical bottom region where breakdown occurs, while the overall compact design maintains acceptable current path length and on-resistance.
3Manufacturing precision
If p-type regions are added below the gate and between conductive regions, then electric field distribution is improved and breakdown voltage increases, but device structure and manufacturing complexity increase
Solution Approach 1:
The patent introduces p-type regions with specific impurity concentrations into the semiconductor structure. A first p-type region is formed below the gate electrode, and a second p-type region is formed between the first and second conductive regions. These p-type regions have impurity concentrations that differ from the surrounding n-type drift region, creating favorable electric field distribution that increases breakdown voltage. The parameter changes in impurity concentration and region positioning resolve the contradiction between improved breakdown voltage and increased structural complexity.
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first conductive portion, a semiconductor portion including silicon carbide, and a first insulating portion. The semiconductor portion includes first to fourth semiconductor regions. The first semiconductor region includes first and second partial regions. The third semiconductor region is provided between the second partial region and the second semiconductor region. The fourth semiconductor region is provided between the first conductive portion and the first partial region. The first insulating portion includes first to third portions. A portion of the first portion is positioned between the first conductive portion and the fourth semiconductor region. The second portion is positioned between the second semiconductor region and the portion of the first conductive portion and between the first conductive portion and the third semiconductor region. The third portion is provided between the first and second portions. The third portion has first and second surfaces.