Vertical Stacked Semiconductor Light Emitting Element Current Diffusion
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Solution Overview
Problem
Semiconductor light emitting elements using group III nitride semiconductors face nonuniformity in light output and reduction in light emitting layer area due to electrode formation and p-bonding pad electrode configurations, making it difficult to mount on wiring boards.
Innovation Solution
A semiconductor light emitting element with a configuration that includes a first and second semiconductor layer, conductor portions, connective conductor portions, and a diffusing layer with a reflective property, arranged in a staggered configuration to minimize light emitting layer area reduction and nonuniformity, using a multi-layer reflecting film for insulation and light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If linear electrodes are formed on the n-type semiconductor layer to diffuse electric current, then current diffusion is improved, but the light emitting layer area is reduced due to removal at electrode portions
Solution Approach 1:
The patent transitions from planar electrode arrangement to three-dimensional vertical stacking. Multiple light emitting layers are stacked in the vertical direction, allowing electrodes to be positioned between layers rather than removing large areas from a single layer. This dimensional change enables current diffusion without sacrificing the effective light emitting area of each individual layer.
Solution Approach 2:
The patent divides a single large light emitting layer into multiple smaller light emitting layers stacked vertically. Each layer can be independently optimized and contributes to the overall light output. This segmentation allows electrodes to access n-type and p-type regions between layers without removing significant area from any single light emitting layer.
2Manufacturing precision
If multiple p-bonding pad electrodes are provided on the p-type semiconductor layer, then current diffusion is improved, but mounting on wiring boards becomes difficult
Solution Approach 1:
The patent merges multiple bonding pad functions into integrated electrode structures positioned between stacked light emitting layers. Rather than having separate p-bonding pads distributed on the p-type layer surface, the electrodes are combined into unified vertical contact structures that connect through the stack, simplifying the bonding interface while maintaining current diffusion benefits.
3Reliability
If electrodes are formed by removing light emitting layer portions, then electrical connection is achieved, but light output is reduced due to area loss
Solution Approach 1:
The patent moves electrode placement from the planar dimension to the vertical dimension by stacking light emitting layers. Electrodes are positioned in the interlayer spaces vertically, eliminating the need to remove light emitting material for electrode access. This preserves 100% of the light emitting area in each layer while achieving reliable electrical connections through the vertical stack architecture.
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 suppresses nonuniformity of light output and reduces the area reduction of the light emitting layer, facilitating easier mounting on wiring boards while maintaining efficient light emission.
Implementation Method 1
a multi-layer reflecting film for insulation and light reflection
Implementation Method 2
a diffusing layer with a reflective property, arranged in a staggered configuration
Data Source
AI summary
Disclosed is a semiconductor light emitting element (1) which includes: plural n-side columnar conductor portions (183), each of which is provided by penetrating a p-type semiconductor layer (160) and a light emitting layer (150), and is electrically connected to an n-type semiconductor layer (140); an n-side layer-like conductor portion (184), which is disposed on the rear surface side of the p-type semiconductor layer (160) to face the surface of the light emitting layer (150) when viewed from the light emitting layer (150), and is electrically connected to the n-side columnar conductor portions (183); plural p-side columnar conductor portions (173), each of which is electrically connected to the p-type semiconductor layer (160); and a p-side layer-like conductor portion (174), which is disposed on the rear surface side of the p-type semiconductor layer (160) to face the light emitting layer (150) when viewed from the light emitting layer (150), and is electrically connected to the p-side columnar conductor portions (173). Thus, nonuniformity of the quantity of light outputted from the light emitting layer of the semiconductor light emitting element is suppressed, and reduction of the area of the light emitting layer in the semiconductor light emitting element is suppressed.