Semiconductor Light Emitting Device Inclined End Face Reflection
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Solution Overview
Problem
Existing semiconductor light emitting devices face challenges in achieving high light intensity and stable electric characteristics due to limitations in reflecting light efficiently from the side of the substrate, particularly with issues related to the inclination angle of the end face and the proximity of electrodes to the luminescent layer, leading to light loss and potential short circuits.
Innovation Solution
The semiconductor light emitting device incorporates a first terrace parallel to the substrate surface and an inclined end face region closer to the substrate, with a reflective electrode disposed in the inclined end face region, allowing for a larger distance between the electrode and the luminescent layer while maintaining efficient light reflection. Additionally, partition grooves are used to divide the semiconductor layer, and a method involving heat treatment and dry etching is employed to precisely form the inclined end faces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the electrode is disposed close to the luminescent layer to reflect light efficiently, then light reflection efficiency is improved, but the risk of short circuiting increases
Solution Approach 1:
The patent introduces a third dimension by forming an inclined end face on the semiconductor layer. Instead of placing the electrode close to the luminescent layer in the planar direction (which causes short circuiting), the inclined surface allows the electrode to be positioned close in the vertical direction while maintaining safe horizontal distance, thus resolving the contradiction between light reflection efficiency and short circuiting risk
Solution Approach 2:
The patent applies asymmetry by creating a non-symmetric inclined end face structure. The inclined surface at a specific angle (30-60 degrees) provides asymmetric light reflection paths, allowing efficient light extraction while maintaining proper electrode spacing to prevent short circuits
2Illumination intensity
If the end face is formed with a precise inclination angle to reflect light efficiently, then light emission intensity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by forming the inclined end face structure before electrode deposition. The inclined surface is created on the semiconductor layer prior to placing the reflective electrode, allowing the electrode to be positioned optimally on the inclined surface without requiring post-alignment adjustments, thus reducing manufacturing precision requirements
3Device complexity
If a translucent electrode is used to emit light from the semiconductor layer side, then device structure is simplified, but light output loss increases
Solution Approach 1:
The patent applies inversion by flipping the traditional light emission configuration. Instead of emitting light from the semiconductor layer side through a translucent electrode, the device emits light from the substrate side using a reflective electrode on the inclined end face. This inverted approach eliminates the need for translucent electrodes and significantly reduces light output loss
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 enhances light reflection and emission intensity from the substrate surface, reduces short circuiting risks, and allows for easier manufacturing, resulting in a more reliable and efficient semiconductor light emitting device with improved power output capabilities.
Implementation Method 1
an inclined end face region which is disposed nearer to the substrate than the first terrace... A reflective first electrode which is disposed in the inclined end face region... reflect light in a desired direction
Implementation Method 2
a second step of subjecting the developed resist layer to a heat treatment in a predetermined condition to shrink the top face of the resist layer, thereby forming the resist layer with an inclined end face at a predetermined angle
Implementation Method 3
a third step of subjecting the semiconductor layer to dry etching by use of the resist layer with the inclined end face as an etching mask to form a concave section an end face of which is inclined at a predetermined angle
Data Source
AI summary
A semiconductor light emitting device can have stable electric characteristics and can emit light with high intensity from a substrate surface. The device can include a transparent substrate and a semiconductor layer on the substrate. The semiconductor layer can include a first conductive type semiconductor layer, a luminescent layer, a second conductive type semiconductor layer, and first and second electrodes disposed to make contact with the first and second conductive type semiconductor layers, respectively. The first conductive type semiconductor layer, the luminescent layer, and the second conductive type semiconductor layer can be laminated in order from the side adjacent the substrate. An end face of the semiconductor layer can include a first terrace provided in an end face of the first conductive type semiconductor layer in parallel with the substrate surface, and an inclined end face region provided nearer to the substrate than the first terrace. The first electrode disposed in the inclined end face region can reflect light emitted from the luminescent layer to the substrate.