Semiconductor Light Emitting Element Warpage Control via Re-growth Layer
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Solution Overview
Problem
The manufacturing of semiconductor light emitting elements with compound semiconductor layers faces issues due to warping of substrates caused by differences in thermal expansion coefficients, leading to irregular wavelength distributions and reduced product yield, particularly when using substrates different from the semiconductor material.
Innovation Solution
A method involving the use of a compound semiconductor substrate with controlled warping within a specific range, where a re-growth layer is laminated in a metalorganic chemical vapor deposition apparatus, along with n-type and p-type semiconductor layers, to achieve a stable wavelength distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a substrate made from a material different from the compound semiconductor is used, then manufacturing cost and ease of manufacture are improved, but warping occurs due to thermal expansion differences causing wavelength distribution standard deviation to increase
Solution Approach 1:
The patent applies preliminary action by forming a buffer layer and underlying layer before forming the light emitting layer. These preliminary layers are designed with specific thicknesses and material compositions to compensate for thermal expansion differences between the substrate and compound semiconductor, thereby preventing warping before it affects the final product quality.
Solution Approach 2:
The patent utilizes parameter changes by carefully controlling the thickness, material composition, and thermal properties of the buffer layer and underlying layer. By adjusting these parameters, the overall thermal expansion characteristics of the layered structure are modified to match the substrate, eliminating warping and maintaining wavelength distribution precision.
2Productivity
If MOCVD method is used to form compound semiconductor layer, then manufacturing efficiency is improved, but warping-induced temperature distribution causes irregular element distribution and reduced product yield
Solution Approach 1:
The patent introduces the buffer layer and underlying layer as intermediary structures between the substrate and the light emitting layer. These intermediary layers act as a mediator that absorbs thermal expansion mismatches, ensuring uniform temperature distribution during MOCVD processing and preventing irregular element distribution that would reduce product yield.
Solution Approach 2:
The patent employs composite material structures consisting of multiple layers with different material properties. The buffer layer and underlying layer are composed of materials specifically selected to provide thermal expansion compensation, creating a composite structure that maintains dimensional stability during high-temperature MOCVD processing while preserving product yield.
3Manufacturing precision
If warping amount is reduced to improve wavelength uniformity, then manufacturing precision is improved, but substrate design complexity and process complexity increase
Solution Approach 1:
The patent applies local quality by designing the buffer layer and underlying layer with specific local properties (thickness, material composition, thermal conductivity) that are optimized for thermal expansion compensation. Rather than uniformly modifying the entire substrate, the solution is localized to specific intermediate layers, maintaining overall process simplicity while achieving wavelength uniformity.
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 reduces the wavelength distribution standard deviation of semiconductor light emitting layers, improving product yield and acceptance rates by controlling substrate warping and growth conditions.
Implementation Method 1
laminating a re-growth layer of the compound semiconductor layer, and an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer that have a composition different from the composition of the compound semiconductor layer on the compound semiconductor layer of the compound semiconductor substrate in a metalorganic chemical vapor deposition apparatus
Implementation Method 2
warping occurs in the substrate mainly due to a difference in coefficient of thermal expansion between the substrate and the compound semiconductor
Data Source
AI summary
Provided is a method of manufacturing a semiconductor light emitting element that is capable of making a light emitting wavelength distribution σ of a semiconductor light emitting layer that is obtained small. The method includes a process of laminating a re-growth layer of a compound semiconductor layer on the compound semiconductor substrate which is obtained by forming at least one compound semiconductor layer on a substrate and in which a warping amount H is within a range of 50 μm≦H≦250 μm. The method adopts a method of manufacturing a semiconductor light emitting element including an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer that are formed from a compound semiconductor. This method includes: a process of preparing a compound semiconductor substrate which is obtained by forming at least one compound semiconductor layer on a substrate and in which a warping amount H is within a range of 50 μm≦H≦250 μm; and a process of laminating a re-growth layer of the compound semiconductor layer on the compound semiconductor layer of the compound semiconductor substrate in a metalorganic chemical vapor deposition apparatus.