Nitride Semiconductor Mask Segmentation for Crystallinity and Removal
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Solution Overview
Problem
Existing methods for manufacturing light-emitting elements face challenges in improving the crystallinity of nitride semiconductor layers grown using masks and efficiently removing the masks without degrading the semiconductor layers.
Innovation Solution
A method involving the formation of a mask with a silicon oxide film as the first layer and a tungsten film as the second layer, where the tungsten film has a higher melting point than the growth temperature, allows for improved crystallinity of nitride semiconductor layers and easy mask removal by lift-off, reducing defects and anomalous growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask is used to grow nitride semiconductor layers selectively, then the crystallinity of the grown layers is improved, but the mask removal becomes difficult
Solution Approach 1:
The mask is divided into two distinct layers: a lower layer (first film) made of silicon oxide and an upper layer (second film) made of tungsten. This segmentation allows each layer to serve different functions - the silicon oxide layer provides a good interface for epitaxial growth improving crystallinity, while the tungsten layer provides mechanical strength and enables easy removal through lift-off after growth.
Solution Approach 2:
The invention changes the material parameters of the mask layers, specifically selecting silicon oxide for the lower layer due to its compatibility with nitride semiconductor epitaxial growth, and tungsten for the upper layer due to its high melting point and ease of removal. These parameter changes resolve the contradiction between improving crystallinity and enabling easy mask removal.
2Ease of manufacture
If the mask is removed easily, then the manufacturing process is simplified, but the crystallinity of the nitride semiconductor layer may be degraded
Solution Approach 1:
By segmenting the mask into two layers with different material properties, the invention achieves both easy removal (through tungsten lift-off) and high crystallinity (through silicon oxide interface). The segmentation allows the beneficial properties of each material to be utilized without compromise.
Solution Approach 2:
The mask is constructed as a composite structure combining silicon oxide and tungsten layers. This composite material approach allows the system to exhibit both the growth-promoting properties of silicon oxide and the easy-removal properties of tungsten, resolving the contradiction between manufacturing ease and product quality.
3Device complexity
If a single-layer mask is used, then the mask structure is simple, but the crystallinity of the nitride semiconductor layer is insufficient
Solution Approach 1:
The mask is segmented into two functional layers: silicon oxide for improving epitaxial growth and crystallinity, and tungsten for providing mechanical strength and enabling easy removal. This segmentation achieves high crystallinity without significantly increasing process complexity, as both layers can be deposited using standard techniques.
Solution Approach 2:
The dual-layer composite mask structure combines the advantages of different materials to achieve high crystallinity. The silicon oxide layer provides a favorable interface for nitride semiconductor growth, while the tungsten layer adds mechanical stability, together resolving the contradiction between structural simplicity and crystallinity enhancement.
4Ease of manufacture
If the mask material has low melting point, then the mask can be removed easily, but the mask cannot withstand the high temperature of nitride semiconductor layer formation
Solution Approach 1:
The mask is segmented into a lower layer (silicon oxide) that can withstand high temperatures during epitaxial growth and an upper layer (tungsten) that provides mechanical strength and enables easy removal. This segmentation allows each layer to be optimized for its specific function without compromise.
Solution Approach 2:
The composite mask structure combines silicon oxide with high temperature resistance and tungsten with easy removability. This composite approach resolves the contradiction between temperature resistance and removal ease, as each material contributes its superior property to the overall mask system.
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 approach enhances the crystallinity of nitride semiconductor layers and facilitates efficient mask removal, reducing defects and allowing for the formation of high-quality light-emitting elements with improved output and reduced size.
Implementation Method 1
The second film has a melting point higher than a temperature of forming the third nitride semiconductor layer
Implementation Method 2
In the removing of the mask, lift-off of the mask is performed by removing the second film by removing the first film
Data Source
AI summary
A method for manufacturing a light-emitting element comprises: forming a mask comprising a first film and a second film such that the mask covers a first active layer and a second nitride semiconductor layer, which comprises: forming the first film covering at least an upper surface of the second nitride semiconductor layer, and forming the second film covering the first film; while the first active layer and the second nitride semiconductor layer are covered with the mask, forming a third nitride semiconductor layer at an exposed portion of a first nitride semiconductor layer, wherein a temperature at which the third nitride semiconductor layer is formed is less than a melting point of the second film; and after the forming of the third nitride semiconductor layer, removing the mask, during which lift-off of the mask is performed by removing the first film, which also removes the second film.