SiC Semiconductor Edge Termination Guard Ring Design
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Solution Overview
Problem
Conventional silicon carbide semiconductor devices face limitations in breakdown voltage due to electric field concentration in the edge termination region, leading to potential destruction during high-voltage operations, especially when switching at high speeds.
Innovation Solution
The silicon carbide semiconductor device features a p-type region extending parallel to the four sides of the active region, with identical cross-sectional structures, which helps distribute avalanche current evenly and reduces electric field concentration in the edge termination region, enhancing breakdown capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high voltage is applied to the edge termination region to sustain breakdown voltage, then the device can operate at higher voltages, but electric field concentration in the edge termination region leads to destruction
Solution Approach 1:
The patent applies local quality by creating a guard ring structure with specific impurity concentration gradients in the edge termination region. The guard ring has a first region with higher impurity concentration and a second region with lower impurity concentration, allowing different parts of the edge termination region to have optimized local electrical properties for field distribution and breakdown voltage sustainment
Solution Approach 2:
The patent extends the guard ring structure in the horizontal direction parallel to the semiconductor surface, adding a dimensional aspect to the edge termination region. This horizontal extension allows the guard ring to effectively distribute the electric field across a larger area, reducing concentration effects while maintaining vertical breakdown capability
2Ease of manufacture
If conventional edge termination structures are used, then device fabrication is simpler, but breakdown capability is limited by electric field concentration
Solution Approach 1:
The patent utilizes parameter changes by controlling impurity concentration distributions through ion implantation or diffusion processes. The guard ring structure features specific impurity concentration profiles (higher in the first region, lower in the second region) that are achieved through controlled manufacturing parameters, enabling enhanced breakdown capability while maintaining fabrication feasibility
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 configuration significantly improves the breakdown capability of the edge termination region by at least twice that of conventional structures, reducing the likelihood of destruction and enabling reliable high-voltage operations.
Implementation Method 1
the first p-type region extends in a horizontal direction parallel to a main surface of the silicon carbide semiconductor substrate... helps distribute avalanche current evenly and reduces electric field concentration in the edge termination region
Data Source
AI summary
A silicon carbide semiconductor device has a rectangle-shaped active region in which a main current flows, and a termination region surrounding the active region in a plan view. The device includes a silicon carbide semiconductor substrate of a first conductivity type, a first semiconductor layer of the first conductivity type on the front surface of the substrate, a second semiconductor layer of a second conductivity type, at a surface at the first semiconductor layer, a first semiconductor region of the first conductivity type, selectively provided in the second semiconductor layer, the second semiconductor region disposed from a periphery of the active region to reach the termination region, and extending along each of directions of four sides of the active region. At the four sides of the active region, a cross-sectional structure of each layer and each region of the device is identical to one another.