Superjunction Termination Hexagonal Lattice Design
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Solution Overview
Problem
Conventional superjunction power semiconductor devices are susceptible to avalanche breakdown at the interface between the active cells and the dense p-columns in the transition region due to symmetry breaking in the lattice structure, leading to weak points in the device.
Innovation Solution
The transition region of the superjunction power semiconductor device is redesigned with a pattern of columns arranged in a hexagonal lattice pattern, where one group of columns is positioned at the corners and another group at the centroid of equilateral triangles, increasing the density and improving the breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional hexagonal lattice transition region with offset is used, then the device structure is simpler to manufacture, but the breakdown voltage is reduced due to symmetry breaking creating weak points
Solution Approach 1:
The patent applies asymmetry by intentionally breaking the conventional hexagonal lattice symmetry through offsetting the p-column positions. This creates a non-uniform distribution where columns are positioned at specific fractional offsets (e.g., 1/3 or 2/3) of the lattice constant, which eliminates weak points and enhances avalanche breakdown characteristics while maintaining manufacturing feasibility
Solution Approach 2:
The patent implements local quality by creating regions with different column densities and positions within the transition region. By varying the p-column placement locally (using different offset patterns in different areas), the device achieves optimized breakdown characteristics in critical regions while maintaining overall structural integrity
2Reliability
If the transition region interface is made denser to improve breakdown voltage, then the susceptibility to avalanche breakdown is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by systematically varying the p-column position parameters (offset distances from lattice points) to optimize the transition region density. By adjusting these positional parameters, the device achieves higher column density and improved breakdown resistance while maintaining precision within standard manufacturing capabilities
Data Source
AI summary
A superjunction device that includes a termination region having a transition region adjacent the active region thereof, the transition region including a plurality of spaced columns.