Vertical Electrode Light Emitting Device Structure
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Solution Overview
Problem
Conventional light emitting devices with lateral electrode structures face limitations in light extraction efficiency and reliability due to the presence of pads on the semiconductor layer, which restrict the expansion of the light emitting area.
Innovation Solution
A vertical electrode type light emitting device structure is introduced, eliminating pads on the semiconductor layer and incorporating a support member, insulating layers, and lead electrodes to enhance light extraction and reliability, while maintaining efficient current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a lateral electrode structure with pads on the semiconductor layer is used, then the device structure is simple and easy to manufacture, but the light extraction efficiency is limited and the light emitting area is restricted
Solution Approach 1:
The patent inverts the conventional lateral electrode structure by implementing vertical electrodes that extend through the semiconductor layer. The contact electrode connects to the first conductive type semiconductor layer and extends downward through the active layer and second conductive type semiconductor layer to connect with the conductive layer, creating a vertical current path that eliminates the need for surface pads and enables full-area light emission.
Solution Approach 2:
The patent transitions from a two-dimensional lateral electrode structure to a three-dimensional vertical electrode structure. The electrodes are arranged vertically with different heights, creating a multi-level configuration where the contact electrode extends deeper than the second electrode, allowing current injection from the top surface while maintaining electrical connection through the bulk material.
2Device complexity
If pads are present on the semiconductor layer, then the electrical connection is simplified, but the light emitting area cannot be expanded
Solution Approach 1:
The patent extracts and removes the conventional surface pads from the semiconductor layer top surface. By eliminating the pads that would block light emission, the entire top surface of the first conductive type semiconductor layer becomes available for light extraction, significantly expanding the effective light emitting area.
Solution Approach 2:
The patent implements a nested electrode configuration where the contact electrode is positioned within the structure formed by the first and second electrodes. The contact electrode extends vertically through the semiconductor layers and is surrounded by the insulating layer, creating a nested arrangement that allows all electrodes to coexist without interfering with light emission from the top surface.
3Reliability
If a vertical electrode structure is implemented, then the light emitting area is increased and light extraction efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
The patent introduces an insulating layer as an intermediary element that fills the space between the contact electrode and the first electrode, and between the contact electrode and the second electrode. This insulating layer prevents electrical shorting between adjacent electrodes while allowing the vertical structure to maintain its compact form, thus managing the complexity introduced by the multi-electrode vertical configuration.
4Reliability
If the contact electrode extends deep into the semiconductor layer, then current distribution is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the geometric parameters of the vertical electrode structure, including the relative heights of the contact electrode versus the first and second electrodes, and the spacing between electrodes. By carefully controlling these dimensional parameters and the depth of electrode extension into the semiconductor layer, the patent achieves uniform current distribution while maintaining manufacturability through standardized fabrication processes.
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
The vertical electrode structure improves light extraction efficiency and increases the light emitting area, leading to enhanced reliability and performance of the light emitting device.
Implementation Method 1
an adhesive layer under the conductive layer
Data Source
Figure 1~3
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Figure 6~8
AI summary
Disclosed are a light emitting device and a light emitting device package having the same. The light emitting device (100) includes a light emitting structure layer (135) including a first conductive type semiconductor layer (110), an active layer (120) under the first conductive type semiconductor layer, and a second conductive type semiconductor layer (130) under the active layer; a conductive layer (140) under the second conductive type semiconductor layer; an adhesive layer (145) under the conductive layer; a support member (150) under the adhesive layer; a contact electrode (171) connected to the first conductive type semiconductor layer; a first lead electrode (175) under the support member; a first electrode (173) connecting the contact electrode to the first lead electrode (175) on a first region of the support member; a second electrode (183) connected to at least one of the conductive layer and the adhesive layer on a second region of the support member; a second lead electrode (185) connected to the second electrode under the support member; and an insulating layer (165) between the contact electrode (171) and the light emitting structure layer (135).