Semiconductor Termination Structure for Voltage Breakdown Prevention
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Solution Overview
Problem
High-voltage semiconductor devices face challenges in preventing voltage breakdown at the edge due to space charge penetration into the termination area, which deteriorates the performance of the termination structure.
Innovation Solution
A novel edge termination structure is implemented, featuring a junction termination extension (JTE) region with a first doped region having a linearly-degraded doping profile away from the active area and at least one second doped region with a linearly-degraded doping profile towards the active area, both with different conductivity types, to reduce space charge effects and enhance electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional termination structure is used, then the device can operate at high voltage, but space charge penetrates into the termination area causing voltage breakdown
Solution Approach 1:
The patent applies local quality by creating a termination structure with spatially varying doping concentrations. The first doped region has doping concentration that gradually decreases away from the active area, while the second doped region has doping concentration that gradually increases away from the active area. This local variation in doping properties effectively distributes and reduces space charge accumulation in specific termination areas, preventing voltage breakdown at device edges.
Solution Approach 2:
The patent implements parameter changes by modifying the doping concentration profiles in the termination structure. The first doped region exhibits a linearly-degraded doping profile away from the active area, while the second doped region shows a linearly-degraded profile towards the active area. These parameter variations in doping concentration effectively control space charge distribution and enhance voltage breakdown resistance in the termination region.
2Reliability
If the termination structure is enhanced to prevent space charge penetration, then voltage breakdown is prevented, but the device structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the termination structure into distinct doped regions: a first doped region with conductivity type opposite to the substrate and a second doped region with the same conductivity type as the substrate. Each region has specific doping concentration profiles that work together to prevent space charge penetration. This segmented approach achieves reliable voltage breakdown prevention while maintaining manageable structural complexity through clear regional differentiation.
Data Source
AI summary
A semiconductor device is disclosed. A substrate of a first conductivity type is provided. The substrate has a first area and a second area. An epitaxial layer of a second conductivity type is disposed on the front side of the substrate. A first doped region of the first conductivity type is disposed in the epitaxial layer in the first area, wherein a doping depth of the first doped region is gradually decreased away from the second area. At least one second doped region of the second conductivity type is disposed in the first doped region, wherein a doping depth of the at least one second doped region is gradually increased away from the second area. A dielectric layer is disposed on the epitaxial layer. A first conductive layer is disposed on the dielectric layer.