Hexagonal Trench Recess Rotates to Suppress Current Concentration
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Solution Overview
Problem
Conventional Group III nitride semiconductor devices with recess structures face challenges in precisely reproducing small patterns due to photolithography limitations, leading to current concentration at trench corners and complex manufacturing processes.
Innovation Solution
A semiconductor device with a trench and recess structure featuring a regular polygon pattern where the sides of the recess are not parallel to the trench, and the Mg activation ratio is lower near the trench corners, allowing for improved reproducibility and reduced current concentration, achieved through specific etching and activation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If photolithography is used to form the recess pattern, then the manufacturing process is simple, but the pattern reproduction precision deteriorates due to the small size of the recess
Solution Approach 1:
The patent changes the geometric parameters of the recess pattern by rotating it relative to the trench, creating an asymmetric configuration where the distance from trench corners to the recess is greater than the distance from trench sides to the recess. This parameter change allows the recess to suppress current concentration at trench corners while maintaining manufacturability through standard photolithography processes.
2Ease of manufacture
If the recess pattern is aligned parallel to the trench, then the manufacturing process is simple, but current concentration occurs at the trench corners
Solution Approach 1:
The patent applies asymmetry by rotating the recess pattern so that its sides are not parallel to the trench sides, creating an asymmetric geometric relationship. Specifically, the distance from each trench corner to the nearest recess is made greater than the distance from each trench side to the nearest recess. This asymmetric configuration redistributes the electric field and suppresses current concentration at the trench corners, improving device reliability.
3Manufacturing precision
If OPC is used to correct the mask pattern, then the pattern reproduction precision is improved, but the manufacturing process becomes complex and time-consuming
Solution Approach 1:
Instead of using OPC to modify the mask pattern to achieve the desired recess shape, the patent inverts the approach by using a simple circular mask pattern and achieving the desired effect through the relative geometric relationship (rotation) between the circular recess and the hexagonal trench. This eliminates the need for complex OPC while still achieving precise pattern reproduction and current suppression.
Data Source
AI summary
The present invention provides a Group III nitride semiconductor device in which current concentration at the corners of the trench is suppressed. The semiconductor device has a pattern in which regular hexagonal unit cells are arranged in a honeycomb pattern. The semiconductor layer is sectionalized into regular hexagonal patterns by the trench. The recess has a small regular hexagonal pattern contained in the regular hexagonal pattern of the semiconductor layer sectionalized by the trench, which is obtained by reducing the regular hexagon of the semiconductor layer with the same center. Moreover, the regular hexagonal pattern of the recess is rotated by 30° with respect to the regular hexagon of the semiconductor layer. The Mg activation ratio is lower in the vicinity of corners of the trench than that in other regions in the vicinity of side walls of the trench of the p-type layer.