SiC Edge Termination Structure for Field Shielding
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Solution Overview
Problem
Conventional edge termination structures in silicon carbide (SiC) semiconductor components are less effective and more complex to produce due to steep pn junctions, particularly in materials with small dopant diffusion coefficients, leading to inefficient lateral field reduction and stability issues.
Innovation Solution
An edge termination structure in SiC semiconductor components comprising a first doped region of a second conductivity type surrounding the active region, with multiple second doped regions of the same conductivity type and third doped regions of the opposite conductivity type, which reduces electric field strength and enhances stability by shielding steep lateral pn junctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional edge termination structures are used in SiC semiconductor components, then the structure is simpler to produce, but the lateral field reduction is less effective and the component exhibits stability issues
Solution Approach 1:
The edge termination structure is segmented into multiple distinct doped regions: a first doped region of second conductivity type, multiple second doped regions of second conductivity type, and third doped regions of first conductivity type. These segmented regions work together to reduce lateral electric field strength more effectively than conventional single-structure edge terminations, improving reliability without requiring overly complex manufacturing processes.
Solution Approach 2:
Different doped regions are assigned specific local functions within the edge termination structure. The first doped region provides initial field reduction, the second doped regions provide additional shielding at different locations, and the third doped regions offer complementary field management. This local differentiation of properties allows the structure to address stability issues through targeted doping rather than uniform complexity.
2Reliability
If higher dopant doses are used in second doped regions, then lateral electric field strength is reduced more effectively, but the manufacturing precision requirements increase
Solution Approach 1:
The first doped region of second conductivity type is formed in advance, establishing a preliminary field reduction structure before the second doped regions are added. This preliminary action creates a foundation that guides subsequent doping steps, allowing higher dopant doses in second doped regions to be applied more effectively without requiring extreme manufacturing precision, as the overall field distribution is already partially established.
Solution Approach 2:
The first doped region acts as an intermediary between the drift zone and the second doped regions. It mediates the electric field distribution, allowing the second doped regions to use higher dopant doses for enhanced field reduction while the first doped region buffers the overall field management, reducing the precision requirements for the higher-dose doping steps.
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 proposed edge termination structure effectively reduces lateral electric field strength, improves stability, and increases scalability for higher voltage classes by allowing higher dopant doses in second doped regions, thus enhancing the reliability and avalanche robustness of SiC semiconductor components.
Implementation Method 1
The edge termination structure effectively reduces lateral electric field strength, improves stability, and increases scalability for higher voltage classes by allowing higher dopant doses in second doped regions
Implementation Method 2
In semiconductor components composed of semiconductor materials in which the diffusion coefficients of dopants are small, edge termination structures such as are known from conventional silicon technology are less effective or more complicated to produce owing to the steeper pn junctions
Data Source
AI summary
A semiconductor component includes a SiC semiconductor body having an active region and an edge termination structure at least partly surrounding the active region. A drift zone of a first conductivity type is formed in the SiC semiconductor body. The edge termination structure includes: a first doped region of a second conductivity type between a first surface of the SiC semiconductor body and the drift zone, the first doped region at least partly surrounding the active region and being spaced apart from the first surface; a plurality of second doped regions of the second conductivity type between the first surface and the first doped region; and third doped regions of the first conductivity type separating adjacent second doped regions of the plurality of second doped regions from one another in a lateral direction.