GaN Diode Electrode Segmentation for Current Injection
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Solution Overview
Problem
The existing semiconductor diodes, particularly gallium nitride light-emitting diodes, face challenges in efficiently injecting electrical supply current due to high resistivity in N-type doped gallium nitride cathode regions and high series resistance, leading to potential differences between diodes and stringent insulation requirements.
Innovation Solution
The diodes are designed with concentric, coplanar structures where each diode's active region is surrounded by trenches, allowing extended contact regions between consecutive diodes, and a novel cathode electrode arrangement with a polygonal ring and rectilinear bars for improved current distribution and reduced series resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional diode structures with limited contact regions are used, then manufacturing is simpler, but series resistance is high and current injection is inefficient
Solution Approach 1:
The cathode electrode is segmented into multiple conductive elements arranged in a specific pattern (polygonal ring with radial bars and parallel bars), where each element serves as a separate current injection path. This segmentation increases the total contact area with the cathode layer and distributes current more uniformly, reducing series resistance while maintaining manageable structural complexity through modular design
Solution Approach 2:
The electrode structure transitions from a simple planar contact to a multi-dimensional conductive network extending in multiple directions (radial bars from ring vertices, parallel bars extending from radial bars). This dimensional expansion increases the effective contact area and current distribution pathways without proportionally increasing manufacturing complexity
Solution Approach 3:
Different regions of the electrode structure provide different functions: the polygonal ring provides peripheral contact, radial bars provide intermediate contact zones, and parallel bars extend contact areas toward the center. This local differentiation optimizes current distribution across the cathode surface, improving injection efficiency while allowing each region to be manufactured using standard techniques
2Ease of operation
If extended contact regions between diodes are implemented, then series resistance is reduced, but device complexity and insulation requirements increase
Solution Approach 1:
Adjacent diodes share common electrode structures and contact regions, merging previously separate interconnection elements into shared components. This merging reduces the total number of discrete interconnection elements needed, lowers series resistance through extended contact areas, and simplifies the overall interconnection structure by eliminating redundant components
Solution Approach 2:
The extended contact regions and shared electrode structures create equipotential zones between adjacent diodes, equalizing potential distributions across interconnection areas. This reduces potential differences and associated insulation requirements while maintaining low series resistance, balancing ease of operation with manageable device complexity
Data Source
Figure 1~2
Figure 3A~3B
Figure 4~5B
AI summary
The invention relates to a diode comprising a vertical stack of first and second semiconductor regions of opposite conductivity types, and a first biasing electrode (801) of its first region disposed in a trench extending from the face of the second region opposite the first region, the first electrode (801) comprising, in top view, the following conducting elements: a polygonal ring (801A); for each vertex of the polygonal ring (801A), a first straight bar (801B) extending between the vertex and the center of the ring, substantially in a direction from the vertex to the center of the ring; and for each first bar (801B), a plurality of second straight bars (801C) extending from the first bar (801B) substantially parallel to the sides of the ring (801A) from the vertex of which the first bar (801B) originates.