SiC Semiconductor Electrode Extension for Field Relaxation
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Solution Overview
Problem
Existing silicon carbide semiconductor devices face challenges in achieving high breakdown voltage, particularly due to inadequate consideration of the electrode structure's impact on electric field concentration, which is not fully addressed by existing termination region designs.
Innovation Solution
A silicon carbide semiconductor device design incorporating a silicon carbide layer with a first and second conductivity type, an element region, a first electric field relaxing region, an insulating film, and an electrode with an extension portion that overlies the relaxing region, enhancing electric field relaxation and increasing breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional termination structures are used in silicon carbide semiconductor devices, then the device structure is simple and easy to manufacture, but the breakdown voltage is insufficient due to inadequate electric field relaxation
Solution Approach 1:
The electrode is divided into multiple segments: a base portion and an extension portion. The extension portion extends from the end of the base portion in the peripheral direction and overlies the electric field relaxing region, creating distinct functional zones within the electrode structure that address different aspects of electric field management.
Solution Approach 2:
The electrode structure transitions from a two-dimensional planar configuration to a three-dimensional structure by adding the extension portion that overlies the electric field relaxing region. This vertical dimensionality enhancement allows the electrode to more effectively relax electric field concentration at the periphery while maintaining structural integrity.
2Reliability
If the electrode is extended to overlie the electric field relaxing region, then electric field concentration is effectively relaxed and breakdown voltage increases, but the device structure becomes more complex
Solution Approach 1:
The extension portion of the electrode is specifically positioned to overlie the electric field relaxing region where electric field concentration occurs. This localized enhancement provides targeted electric field relaxation exactly where needed, improving avalanche resistance without requiring complex modifications throughout the entire device structure.
Solution Approach 2:
The extension portion is designed to extend from the end of the base portion in the peripheral direction, preemptively addressing electric field concentration at the boundary between the element region and the termination region. This preliminary structural arrangement prevents electric field breakdown before it can occur, enhancing device reliability.
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 design effectively increases the breakdown voltage of silicon carbide semiconductor devices by relaxing electric field concentration, thereby improving ruggedness and avalanche resistance.
Implementation Method 1
a first electric field relaxing region having a second conductivity type different from the first conductivity type, the first electric field relaxing region being disposed in the silicon carbide layer so as to be in contact with the first main surface of the silicon carbide layer and so as to surround the element region when viewed two-dimensionally
Implementation Method 2
The extension portion overlies at least a portion of the first electric field relaxing region
Data Source
AI summary
A silicon carbide semiconductor device includes a silicon carbide layer, an element region including a semiconductor element portion formed in the silicon carbide layer, a JTE region (first electric field relaxing region), an insulating film disposed on a first main surface and covering the JTE region, and a pad electrode electrically connected to the JTE region. The pad electrode includes an extension portion extending from an end of the JTE region close to the element region in a peripheral direction from the element region toward the JTE region, the extension portion being disposed on the insulating film. The extension portion overlies at least a portion of the JTE region.