SiC Edge Termination Rings for Breakdown Field Control
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Solution Overview
Problem
Existing edge termination structures for silicon carbide integrated power devices face limitations in achieving high breakdown voltages due to electric field peaks and material differences from silicon, leading to premature aging and reliability issues.
Innovation Solution
The implementation of a concentric ring structure with transition regions and charge control regions in the edge termination structure, formed through multiple dopant implants, which reduces electric field peaks by controlling charge density and approximates a continuous degrading profile, compatible with lithographic techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single ring region is formed around the main junction, then the manufacturing process is simple, but the electric field distribution cannot be accurately controlled
Solution Approach 1:
The single ring region is divided into multiple concentric ring regions with different widths and doping concentrations. This segmentation allows independent control of electric field distribution in different radial zones, enabling accurate electric field management while maintaining a relatively simple manufacturing process using sequential implantation steps.
Solution Approach 2:
Different regions of the ring structure are assigned different doping concentrations and widths to create locally optimized electric field control. The inner regions have different properties than outer regions, allowing the electric field to be precisely shaped and controlled at each location to prevent peak formation.
2Manufacturing precision
If multiple concentric ring regions are formed with variable width and separation distance, then the electric field control is improved, but the device complexity increases
Solution Approach 1:
The edge termination structure is segmented into multiple concentric rings with progressively varying parameters. This segmentation provides the flexibility to control electric field distribution precisely while using systematic design rules that prevent excessive complexity.
Solution Approach 2:
Instead of forming a perfectly continuous gradient, the patent uses discrete ring regions with stepwise variations in width and doping. This partial action approach achieves sufficient electric field control without requiring the excessive complexity of a perfectly continuous structure.
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 approach effectively reduces electric field peaks at interfaces, minimizing stress on materials and preventing premature aging, thereby enhancing the reliability and performance of silicon carbide integrated power devices.
Implementation Method 1
formed through multiple dopant implants
Data Source
Figure 1~2
Figure 3~6
Figure 7~9
AI summary
An integrated device (11) includes: a semiconductor structural layer (5), including silicon carbide and having a first conductivity type; a power device (2) integrated in the structural layer (5); and an edge termination structure (3), extending in a ring around the power device (2) and having a second conductivity type. The edge termination structure (3) includes a plurality of ring structures (10, 11, 12) each arranged around the power device (2) and in contiguous pairs. At least a first one (10, 11) of the ring structures (10, 11, 12) comprises a transition region (10b, 11b) contiguous to a second one (11, 12) of the ring structures (10, 11, 12). The transition region (10b, 11b) includes connection regions (10c, 11c), having the second conductivity type, connected to the second one (11, 12) of the ring structures (10, 11, 12) and alternating with charge control regions (10d, 11d) having the first conductivity type.