Light Emitting Element Structure for Active-Layer Strain Relief
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Solution Overview
Problem
Current light emitting display devices face challenges in reducing strain in the active layer, which can lead to increased defect density and reduced luminous efficiency, particularly when the indium content in the active layer is high, causing aggregation and stress.
Innovation Solution
A method of manufacturing a light emitting element that includes forming a strain relaxed undoped semiconductor layer between the first semiconductor layer and the active layer, using wet etching with etchants like potassium hydroxide or tetramethylammonium hydroxide, and structuring the semiconductor layers to alleviate lattice constant differences, thereby reducing strain and preventing luminous efficiency reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high indium content is used in the active layer to improve light emission properties, then luminous efficiency is improved, but strain and defect density increase
Solution Approach 1:
An undoped semiconductor layer is introduced as an intermediary layer between the first semiconductor layer and the active layer. This intermediate layer acts as a buffer to relieve strain caused by high indium content in the active layer, preventing strain transfer while maintaining the high luminous efficiency benefits of the indium-rich active layer.
Solution Approach 2:
The doping status of the semiconductor layer is changed from doped to undoped, creating a strain-relaxed layer. By changing the doping parameter (from doped to undoped), the layer can accommodate lattice mismatch and reduce strain accumulation, allowing the active layer to maintain high indium content without excessive strain.
2Device complexity
If the semiconductor layer structure is simplified to reduce manufacturing complexity, then device complexity is reduced, but strain management capability deteriorates
Solution Approach 1:
The semiconductor layer structure is segmented into multiple functional layers: a first semiconductor layer, an undoped semiconductor layer, and an active layer. This segmentation allows each layer to perform its specific function - the first semiconductor layer provides structural support, the undoped layer relieves strain, and the active layer emits light - thereby managing strain without significantly increasing overall manufacturing complexity.
3Manufacturing precision
If wet etching is used to form patterns in the undoped semiconductor layer, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The undoped semiconductor layer is designed to be selectively removable through wet etching due to its specific material properties and lack of doping. This self-service characteristic allows the layer to automatically facilitate precise pattern formation through standard wet etching processes without requiring additional complex processing steps, as the undoped nature of the layer makes it inherently more susceptible to selective removal.
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 approach effectively reduces strain in the active layer, preventing defect density increases and indium aggregation, thus maintaining luminous efficiency even with high indium content, and enhancing the overall performance of the light emitting element.
Implementation Method 1
forming an undoped semiconductor layer on the substrate on which the first patterns are formed, etching the undoped semiconductor layer... the undoped semiconductor layer includes second patterns recessed from a lower surface of the undoped semiconductor layer
Implementation Method 2
The etching of the undoped semiconductor layer may be performed by wet etching. An etchant for the wet etching may include potassium hydroxide or tetramethylammonium hydroxide.
Data Source
AI summary
A method of manufacturing a light emitting element, comprises placing a plurality of mask patterns on a substrate, forming first patterns on the substrate through the plurality of mask patterns, the first patterns recessed from an upper surface of the substrate, forming an undoped semiconductor layer on the substrate on which the first patterns are formed, etching the undoped semiconductor layer, forming a first semiconductor layer on the undoped semiconductor layer, forming an active layer on the first semiconductor layer, forming a second semiconductor layer on the active layer, and forming an electrode layer on the second semiconductor layer, wherein the undoped semiconductor layer includes second patterns recessed from a lower surface of the undoped semiconductor layer.