Flip Chip Light Emitting Device with Bottom Electrode and Conductor
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Solution Overview
Problem
Conventional light emitting devices face challenges in achieving flip chip mounting while maintaining mechanical strength and light emission efficiency, as exposed semiconductor layers can lead to breakage and reduced effective light emission areas.
Innovation Solution
A light emitting device with a laminated structure including a first-conductivity type semiconductor layer, a light emitting layer, and a second-conductivity type semiconductor layer, where a contact layer is provided at the peripheral edge of the second-conductivity type semiconductor layer, and a conductor connects the second electrode to the contact layer, allowing for flip chip mounting without exposing the semiconductor layers, thus enhancing strength and light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an exposed portion is provided to a semiconductor layer to enable flip chip mounting, then ease of operation is improved, but strength and light emission efficiency deteriorate
Solution Approach 1:
The patent moves the second electrode from the top surface (where it would create an exposed portion) to the bottom surface of the n-type cladding layer. This dimensional relocation allows both electrodes to be on the same side for flip chip mounting while eliminating the exposed portion problem on the top surface.
Solution Approach 2:
The patent introduces a conductor (wiring line) as an intermediary element that connects the second electrode on the bottom surface to the contact layer on the top surface. This intermediary allows electrical connection without requiring the second electrode to be exposed on the top surface, thus preventing breakage and maintaining light emission efficiency.
2Ease of operation
If an exposed portion is provided to a semiconductor layer to enable flip chip mounting, then ease of operation is improved, but light emission efficiency deteriorates
Solution Approach 1:
The second electrode is relocated to the bottom surface dimension, removing it from the light extraction path on the top surface. This dimensional change eliminates the non-light-emitting region problem while still enabling flip chip mounting through the conductor connection.
Solution Approach 2:
The conductor serves as an intermediary that provides the electrical connection path without occupying the light extraction area. The conductor can be routed through the substrate or along the side surfaces, keeping the top surface fully available for light emission.
3Device complexity
If the second electrode is disposed on the p-type cladding layer side, then device complexity is reduced, but strength deteriorates
Solution Approach 1:
The patent relocates the second electrode to the bottom surface dimension, creating a symmetric configuration where both electrodes are on the same side. This maintains structural simplicity while eliminating the exposed portion that causes strength deterioration.
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 enables flip chip mounting with improved mechanical strength and light emission efficiency by preventing breakage and maintaining a higher effective light emission area, while minimizing light absorption by the contact layer.
Implementation Method 1
a conductor electrically connecting the second electrode and the contact layer to each other
Implementation Method 2
a light emitting layer... extracts light by applying a voltage between electrodes
Data Source
AI summary
A light emitting device includes: a laminated body including a first-conductivity type semiconductor layer, a light emitting layer, and a second-conductivity type semiconductor layer in this order; a contact layer provided in contact with the second-conductivity type semiconductor layer at least at a peripheral edge of the second-conductivity type semiconductor layer; a first electrode electrically connected to the first-conductivity type semiconductor layer; a second electrode provided nearer to the first-conductivity type semiconductor layer than the second-conductivity type semiconductor layer; and a conductor electrically connecting the second electrode and the contact layer to each other.