Three-Dimensional Crossover Electrode Structure for Optoelectronic Semiconductor Devices
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Solution Overview
Problem
Conventional light emitting devices suffer from current crowding, leading to uneven current density distribution, heat accumulation, and reduced efficiency, especially as chip size and driving voltage increase, complicating the electrode structure layout and increasing costs.
Innovation Solution
The optoelectronic semiconductor device features a three-dimensional crossover electrode structure with symmetrical closed patterns of p-type and n-type extension electrodes and bonding pads, allowing for flexible design and stable manufacturing with reduced costs, eliminating the need for removing excessive semiconductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the chip size increases, then the lighting device can handle higher driving voltage and provide more power, but the current distribution becomes uneven due to accumulated resistance, leading to current crowding and heat accumulation
Solution Approach 1:
The electrode structure is divided into multiple segments including bonding pads, extension electrodes, and current spreading layers. The extension electrodes are further segmented into multiple fingers that distribute current across different regions, preventing current crowding and ensuring uniform current distribution even in larger chips with higher driving voltages
Solution Approach 2:
The patent introduces a three-dimensional electrode layout with extension electrodes extending from the bonding pads in specific patterns. This dimensional expansion allows current to spread more effectively across the chip surface, overcoming the resistance accumulation problem that occurs with simple two-dimensional layouts in large chips
2Ease of manufacture
If the conventional vertical type chip design is used with n-type and p-type electrodes on opposite sides, then the electrode structure can be formed, but the epitaxial substrate must be removed to expose the first conductivity type semiconductor layer, complicating the process and reducing yield
Solution Approach 1:
Instead of removing the epitaxial substrate to access the first conductivity type layer from the bottom, the patent forms electrodes on the same surface where the active layer is located. The extension electrodes and bonding pads are configured to contact the first conductivity type semiconductor layer without requiring substrate removal, completely inverting the conventional approach
Solution Approach 2:
The patent extracts the need for substrate removal entirely from the manufacturing process. By designing the electrode structure to access the first conductivity type layer through the same surface, the complex steps of substrate removal, cleaning, and re-epitaxial growth are eliminated, simplifying the process and improving yield
3Manufacturing precision
If the p-type electrode and n-type electrode are positioned close together to reduce resistance, then current distribution improves, but the layout becomes constrained and difficult to optimize for large chip sizes
Solution Approach 1:
The electrode layout is designed with dynamic adaptability through the extension electrode structure. The extension electrodes can be configured in different patterns and lengths depending on the chip size and application requirements, allowing the same basic structure to adapt to various chip dimensions while maintaining optimal current distribution
Solution Approach 2:
The extension electrode structure serves multiple functions: it acts as a current spreading element, a structural support, and a flexible layout component. This multi-functionality allows the same electrode design to be universally applied to different chip sizes and configurations without sacrificing current distribution uniformity or layout flexibility
Data Source
AI summary
An optoelectronic semiconductor device includes a substrate, a semiconductor system having an active layer formed on the substrate and an electrode structure formed on the semiconductor system, wherein the layout of the electrode structure having at least a first conductivity type contact zone or 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 have three-dimensional crossover, and partial of the first conductivity type extension electrode and the first conductivity type contact zone or the first conductivity type bonding pad are on the opposite sides of the active layer.