SiC Semiconductor Guard Ring Curvature for High Voltage Termination
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Solution Overview
Problem
Conventional SiC semiconductor devices have corners with small curvature in high-voltage environments, leading to reduced effective region area and potential failure to handle large electric currents.
Innovation Solution
A semiconductor device design featuring a silicon carbide semiconductor layer with a termination region including a guard ring and field limiting ring structure, where the guard ring has a radius of curvature of 50 μm or less, enhancing the effective region area while maintaining high breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If corners of the effective region have small curvature in conventional SiC semiconductor devices, then the breakdown voltage is maintained, but the area of the effective region is reduced, leading to insufficient electric current handling capability
Solution Approach 1:
The patent applies curvature to the corners of the effective region by forming a guard ring region with a specific radius of curvature (50 μm or less). This curved structure at the corners allows the electric field to be distributed more evenly, preventing field concentration that would limit the breakdown voltage, while simultaneously increasing the effective region area to enhance current handling capability.
Solution Approach 2:
The patent introduces a termination region with different conductivity type (second conductivity type) surrounding the effective region (first conductivity type). This local differentiation creates a guard ring structure that specifically addresses the corner regions, providing localized electric field control without compromising the overall effective region area, thus resolving the contradiction between breakdown voltage and current handling.
2Productivity
If the effective region area is increased to handle large electric current, then the current handling capability is improved, but the breakdown voltage may be reduced due to field concentration at corners
Solution Approach 1:
By forming the guard ring region with a controlled radius of curvature (50 μm or less) at the corners of the effective region, the patent enables the effective region to be expanded for higher current handling while the curved corners prevent electric field concentration that would otherwise reduce breakdown voltage. The curvature distributes the field evenly across the expanded area.
Solution Approach 2:
The termination region with second conductivity type acts as an intermediary structure between the effective region and the substrate. This guard ring structure mediates the electric field distribution, allowing the effective region area to be increased for higher current capacity while maintaining the breakdown voltage through controlled field termination at the corners.
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
The design ensures a sufficient effective region area for high electric current handling without significant reduction in breakdown voltage, enabling reliable operation in high-voltage environments.
Implementation Method 1
The first electrode is disposed on the silicon carbide semiconductor layer and forms a Schottky contact with the silicon carbide semiconductor layer
Implementation Method 2
The second electrode is disposed on the back surface of the semiconductor substrate and forms an ohmic contact with the semiconductor substrate
Implementation Method 3
The termination region also has a guard ring region of a second conductivity type abutting the surface of the silicon carbide semiconductor layer, and a field limiting ring (FLR) region which is disposed to surround the guard ring region
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, a silicon carbide semiconductor layer disposed on the semiconductor substrate, and a termination region disposed in the silicon carbide semiconductor layer. The termination region has a guard ring region and an FLR region which is disposed to surround the guard ring region while being separated from the guard ring region, the FLR region including a plurality of rings. The termination region includes a sector section, and in the sector section, an inner circumference and an outer circumference of at least one of the plurality of rings and an inner circumference and an outer circumference of the guard ring region have a same first center of curvature, the first center of curvature being positioned inside the inner circumference of the guard ring region, and a radius of curvature of the inner circumference of the guard ring region is 50 μm or less.