Three-Dimensional Crossover Electrodes for LED Current Distribution
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Solution Overview
Problem
Conventional light emitting devices suffer from current crowding, leading to uneven current distribution, heat accumulation, and reduced efficiency, particularly as chip size and driving voltage increase, complicating the electrode structure design and increasing costs.
Innovation Solution
A three-dimensional crossover electrode structure is implemented, where first and second conductivity type extension electrodes are positioned on opposite sides of the active layer, allowing for flexible design and stable manufacturing with reduced costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the chip size and driving voltage increase, then the power and brightness of the light emitting device improve, but the current distribution becomes uneven and manufacturing complexity increases
Solution Approach 1:
The patent transitions from a conventional planar electrode layout to a three-dimensional crossover structure where electrodes extend vertically through the chip thickness. This dimensional change allows current to be distributed more uniformly across the active layer by introducing vertical current paths that bypass the resistance accumulation problem inherent in surface-level electrode designs.
Solution Approach 2:
The electrode structure is segmented into multiple components: bonding pads at the surface, extension electrodes that penetrate through the chip, and contact electrodes at the opposite surface. This segmentation allows each component to perform a specific function in the current distribution pathway, improving overall current uniformity while managing the effects of higher driving voltages.
2Manufacturing precision
If the conventional vertical type chip design is used with n-type and p-type electrodes on opposite sides, then the current distribution can be improved, but the manufacturing process becomes complicated and costly
Solution Approach 1:
The patent merges the functions of multiple electrodes into a unified three-dimensional crossover structure. The extension electrodes serve both as current distribution elements and as structural connectors between opposite surfaces, eliminating the need for separate reflecting layers and permanent substrates required in conventional designs.
Solution Approach 2:
The invention extracts and eliminates unnecessary manufacturing steps from the conventional process. By using extension electrodes that directly connect bonding pads to contact electrodes through the chip, the patent removes the need for epitaxial substrate removal, reflecting layer deposition, and permanent substrate formation, thereby simplifying the manufacturing process.
Data Source
AI summary
An optoelectronic semiconductor device including: a substrate; a semiconductor system having an active layer formed on the substrate; and an electrode structure formed on the semiconductor system, wherein the electrode structure includes: a first conductivity type bonding pad; a second conductivity type bonding pad; a first conductivity type extension electrode; and a second conductivity type extension electrode, wherein the first conductivity type extension electrode and the second conductivity type extension electrode form a three-dimensional crossover; wherein the first conductivity type extension electrode and the second conductivity type extension electrode are on the opposite sides of the active layer.