Optoelectronic Layer Stack for Uniform Current Spreading
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Solution Overview
Problem
Current optoelectronic semiconductor devices face challenges in improving current supply and manufacturing cost, particularly in achieving uniform current distribution and reducing radiation losses.
Innovation Solution
The implementation of an optoelectronic semiconductor device with a layer stack comprising a contact layer, a separating layer of lower conductivity than the current spreading layer, and a current spreading layer, where the separating layer is a continuous layer with anisotropic conductivity, formed using techniques like ALD or GLAD, and potentially doped with materials like TiO2 or ZnO, to enhance transverse conductivity and reduce vertical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional current spreading layer is used directly on the contact layer, then current supply is simplified, but current distribution uniformity deteriorates due to current crowding
Solution Approach 1:
The patent segments the current spreading function by introducing a separating layer between the contact layer and the current spreading layer. This segmentation allows the contact layer to provide vertical current access while the current spreading layer distributes current laterally, preventing current crowding and improving current distribution uniformity without complicating the current supply structure.
Solution Approach 2:
The separating layer acts as an intermediary between the contact layer and the current spreading layer. It has lower conductivity than the current spreading layer, which prevents direct vertical current flow from the contact layer to the substrate, thereby forcing current to spread laterally through the current spreading layer and achieving uniform current distribution.
2Ease of manufacture
If radiation losses are not addressed, then manufacturing process remains simple, but light output uniformity deteriorates
Solution Approach 1:
The separating layer serves as an intermediary that reduces radiation losses by preventing direct optical coupling between the light emitting region and the substrate. This layer acts as an optical barrier that reduces parasitic absorption and improves light extraction efficiency, thereby reducing radiation losses without adding complex manufacturing steps.
3Power
If the separating layer has high conductivity, then current supply is improved, but current spreading layer function deteriorates
Solution Approach 1:
The patent applies local quality by giving different conductivity characteristics to different layers: the separating layer has lower conductivity to maintain its separating function, while the current spreading layer has higher conductivity to enable effective current distribution. This localized conductivity differentiation ensures that each layer performs its specific function optimally without interfering with the other.
Solution Approach 2:
The patent uses asymmetry in conductivity design where the current spreading layer has significantly higher conductivity than the separating layer. This asymmetric conductivity structure ensures that current flows preferentially through the current spreading layer in the lateral direction, enabling effective current spreading while the separating layer maintains its role as a current barrier in the vertical direction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves current distribution and light output uniformity by reducing radiation losses and preventing current crowding, while simplifying the manufacturing process by eliminating the need for complex contact hole definitions.
Implementation Method 1
A layer stack which includes the contact layer, the separating layer, and the current spreading layer has an anisotropic conductivity
Implementation Method 2
The separating layer is present as a continuous layer in a region between the contact layer and the current spreading layer
Data Source
AI summary
An optoelectronic semiconductor device may include a first semiconductor layer and a second semiconductor layer, the first and second semiconductor layers being stacked one above the other. The device may include a first contact structure and a contact layer. The device may include a separating layer arranged over a side of the contact layer, and a current spreading layer arranged over a side of the separating layer facing away from the contact layer. The first contact structure may be connected to the contact layer via the current spreading layer and the separating layer. A layer stack may include the contact layer, the separating layer, and the current spreading layer has an anisotropic conductivity. The separating layer is present as a continuous layer in a region between the contact layer and the current spreading layer.