Diode Edge Field Reduction via Segmented Semiconductor Zones
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Solution Overview
Problem
Diodes face challenges in reducing electrical field strengths at the edge region of semiconductor bodies, which can lead to electrical flashovers, and require efficient production methods.
Innovation Solution
A diode design with specific semiconductor zones and doping profiles, including a planar first semiconductor body main side, a second semiconductor zone not extending to the edge, and a third semiconductor zone with higher doping concentration, along with a cutout and passivation layers like silicon oxide and polyimide or glass, to reduce edge electric field strengths and facilitate production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional diode structure with uniform doping is used, then the manufacturing process is simple, but electrical field strengths at the edge region are high causing flashovers
Solution Approach 1:
The semiconductor body is divided into multiple doped zones (first, second, third, and fourth semiconductor zones) with different conduction types and doping concentrations. This segmentation allows the edge region to have different electrical properties than the bulk, reducing field strength concentration at edges while maintaining overall device functionality.
Solution Approach 2:
The fourth semiconductor zone is specifically positioned in the edge region with a doping concentration lower than the third zone. This local variation in doping quality creates a field effect that reduces electrical field strength at the vulnerable edge region, preventing flashovers without compromising the bulk region's electrical performance.
2Reliability
If complex doping profiles and cutouts are implemented, then edge electric field strengths are reduced, but production efficiency decreases
Solution Approach 1:
The cutout structure is formed in advance during the semiconductor manufacturing process, before final device assembly. The second, third, and fourth doped zones are also created in predetermined patterns during fabrication. This preliminary structuring allows the complex edge field management to be achieved without adding post-processing steps, maintaining production efficiency.
3Ease of manufacture
If the first semiconductor body main side is made planar, then contact formation with substrates is simplified, but edge field reduction capabilities are limited
Solution Approach 1:
The solution moves the edge field management from the surface geometry (2D planar structure) to the subsurface doping profile (3D volumetric structure). The planar first main side maintains ease of contact formation, while the fourth semiconductor zone embedded in the edge region at depth provides the necessary field reduction through its specific doping profile, effectively using the third dimension to solve the edge field problem.
Data Source
AI summary
A diode has a semiconductor body having a first and a second semiconductor body main side. The semiconductor body has a first semiconductor zone. The semiconductor body has a second semiconductor zone arranged on the first semiconductor zone in an inner region of the semiconductor body and not extending as far as the semiconductor body edge of the semiconductor body. The semiconductor body has a third semiconductor zone arranged on the second semiconductor zone and has a higher doping concentration than the second semiconductor zone. The semiconductor body has a fourth semiconductor zone arranged on the first semiconductor zone in a semiconductor body edge region and extending from the second semiconductor zone in the direction towards the semiconductor body edge as far as the semiconductor body edge.