Semiconductor Light-Emitting Device Electrode Inversion
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Solution Overview
Problem
Conventional semiconductor light-emitting devices face reduced luminous efficiency due to light absorption by electrodes and require wire bonding, which can lead to short-circuits and limited light extraction.
Innovation Solution
The semiconductor light-emitting device features a p-type and n-type electrode disposed under the semiconductor structure, eliminating the need for wire bonding by forming electrodes on the lower surface, with a contact hole design that includes an inclination angle of 30-60 degrees and a concavo-convex structure to enhance light extraction, and using a reflective second electrode layer to improve luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrode is disposed on the upper surface of a semiconductor layer for current spreading, then current distribution is improved, but light extraction is limited and luminous efficiency is reduced due to light absorption by the electrode
Solution Approach 1:
The patent inverts the conventional electrode placement by moving the electrode from the upper surface to the lower surface of the semiconductor layer. This inversion allows the electrode to supply current without blocking light extraction paths, thereby maintaining current distribution effectiveness while eliminating light absorption losses.
Solution Approach 2:
The patent transitions the electrode placement from a two-dimensional planar configuration on the upper surface to a three-dimensional configuration on the lower surface, enabling current supply through the substrate while preserving the light-emitting area on the upper surface.
2Reliability
If wire bonding is used to supply current to the electrode, then electrical connection is achieved, but the wire may be short-circuited due to heat generated in the device
Solution Approach 1:
The patent extracts and eliminates the wire bonding component from the system by implementing direct electrode contact through the substrate. This removes the vulnerable wire element that could be damaged by heat, while maintaining the electrical connection function through a more robust direct-contact architecture.
3Reliability
If a large electrode area is used for current spreading, then current distribution is improved, but the light-emitting area is reduced
Solution Approach 1:
By inverting the electrode placement to the lower surface, the patent enables the electrode to occupy the full upper surface area for light emission while maintaining adequate current spreading capability through the substrate contact, effectively resolving the area trade-off.
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 maximizes light-emitting area, reduces heat-related issues, and enhances luminous efficiency by minimizing electrode size and eliminating wire bonding, while allowing for direct packaging without the need for wire bonding, thereby improving the reliability and manufacturing efficiency of the devices.
Implementation Method 1
using a reflective second electrode layer to improve luminous efficiency
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A semiconductor light-emitting device, and a method of manufacturing the same. The semiconductor light-emitting device includes a first electrode layer, an insulating layer, a second electrode layer, a second semiconductor layer, an active layer, and a first semiconductor layer that are sequentially stacked on a substrate, a first contact that passes through the substrate to be electrically connected to the first electrode layer, and a second contact that passes through the substrate, the first electrode layer, and the insulating layer to communicate with the second electrode layer. The first electrode layer is electrically connected to the first semiconductor layer by filling a contact hole that passes through the second electrode layer, the second semiconductor layer, and the active layer, and the insulating layer surrounds an inner circumferential surface of the contact hole to insulate the first electrode layer from the second electrode layer.