Edge Termination Subrings for Higher Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor switching devices with edge termination structures often experience electric field peaks during the blocking state, leading to reliability failures and insufficient breakdown voltage (VBR).
Innovation Solution
The implementation of an edge termination structure comprising a series of spaced apart concentric ring sections doped with a second type of charge carriers, which smooths out the electric field by spreading the doping profiles laterally and deeper into the semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional edge termination structure with wide rings is used, then the manufacturing is simpler, but electric field peaks occur during blocking state leading to reliability failures
Solution Approach 1:
The patent divides the conventional wide ring structure into multiple narrow concentric subrings (typically 3-10 subrings per ring). Each subring is doped with the second type of charge carriers and spaced apart by regions doped with the first type of charge carriers. This segmentation smooths the doping profile laterally and eliminates electric field peaks during blocking state, thereby improving device reliability while maintaining manufacturing feasibility through sequential doping steps
2Reliability
If the doping profile is concentrated in wide rings, then the manufacturing process is simpler, but the electric field is not smoothed out leading to insufficient breakdown voltage
Solution Approach 1:
The wide ring is segmented into multiple narrow concentric subrings with spacing between them. This segmentation distributes the doping concentration more uniformly across the termination region, smoothing the electric field and increasing breakdown voltage. The manufacturing complexity is managed through sequential doping processes that can be integrated into existing fabrication flows
Solution Approach 2:
Different regions of the termination structure are doped with different types and concentrations of charge carriers. The subrings are doped with the second type of charge carriers while the spacing regions are doped with the first type, creating a tailored local doping profile that optimizes electric field distribution and breakdown characteristics
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 reduces electric field peaks, thereby enhancing the breakdown voltage (VBR) and improving the reliability of the semiconductor switching device.
Implementation Method 1
each ring section being doped with the second type of charge carriers and being spaced apart by a spacing doped with the first type of charge carriers
Implementation Method 2
The resulting electric field, which is a function of the doping, is smoothed out
Data Source
Figure 1(A)~1(B)
Figure 1C
Figure 2
AI summary
According to a first example of the disclosure, a semiconductor switching device implementing an edge termination structure is proposed. The semiconductor switching device comprises a semiconductor die formed by a first region (111) doped with a first type of charge carriers and having a center area (100y) and a peripheral area (100z) surrounding the center area, and at least one junction provided in the center area of the semiconductor die, the junction being formed with respect to a second region doped with a second type of charge carriers different from the first type of charge carriers, with the second region adjoining the first region. An edge termination structure is provided in the edge area (100z) and surrounding the center area (100y), and structured to prevent voltage breakdown during operation of the semiconductor switching device, the edge termination structure being composed of are least one ring structure (113, 120) provided in the first region, wherein the at least ring one structure is composed of a series of spaced apart concentric ring sections (113) provided in the first region, each ring section being doped with the second type of charge carriers and being spaced apart by a spacing (120) doped with the first type of charge carriers. Each ring section is connected to a field plate (114).