GaN Recrystallization for High-Indium and AlGaN Light Emitters
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Solution Overview
Problem
In manufacturing light-emitting devices based on InGaN or AlGaN, high indium or aluminum concentrations lead to degradation of crystalline quality due to lattice parameter mismatches, limiting the achievable emission spectrum and device performance.
Innovation Solution
The method involves ion implantation of indium or aluminum into a gallium nitride layer to create an amorphous upper portion while preserving the crystal structure of the lower portion, followed by solid phase recrystallization and subsequent deposition of a light-emitting structure, allowing for high indium or aluminum concentrations in the active layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the indium concentration in the InGaN layers of the active layer is increased to shift emission wavelengths toward red, then the emission spectrum coverage is improved, but the crystalline quality of the active layer degrades due to lattice parameter mismatches
Solution Approach 1:
The patent applies preliminary action by performing ion implantation of indium atoms into the GaN layer before the actual epitaxial growth of the active layer. This pre-seeding of indium atoms at controlled depths and concentrations allows the subsequent epitaxial growth to proceed with high crystalline quality while achieving the desired high indium concentration in the InGaN active layer, thus resolving the contradiction between spectrum coverage and crystalline quality
Solution Approach 2:
The patent employs local quality by creating a depth-dependent indium concentration profile through ion implantation. The indium concentration varies with depth, with higher concentrations at certain depths and lower concentrations at others, allowing different regions of the layer to have optimized properties for their specific functions while maintaining overall crystalline quality and achieving broad spectrum coverage
2Adaptability or versatility
If the aluminum concentration in the AlGaN layers of the active layer is increased to shift emission wavelengths toward ultraviolet, then the emission spectrum coverage is improved, but the crystalline quality of the active layer degrades due to lattice parameter mismatches
Solution Approach 1:
The patent applies preliminary action by performing ion implantation of aluminum atoms into the GaN layer before the actual epitaxial growth of the active layer. This pre-seeding of aluminum atoms at controlled depths and concentrations allows the subsequent epitaxial growth to proceed with high crystalline quality while achieving the desired high aluminum concentration in the AlGaN active layer, thus resolving the contradiction between spectrum coverage and crystalline quality
Solution Approach 2:
The patent employs local quality by creating a depth-dependent aluminum concentration profile through ion implantation. The aluminum concentration varies with depth, allowing different regions of the layer to have optimized properties for their specific functions while maintaining overall crystalline quality and achieving broad spectrum coverage
3Adaptability or versatility
If conventional methods are used to manufacture light-emitting cells with high indium or aluminum concentration, then the emission wavelength range is extended, but the device performance degrades due to crystalline quality issues
Solution Approach 1:
The patent applies preliminary action by performing ion implantation of indium or aluminum atoms into the GaN layer before the actual epitaxial growth of the active layer. This pre-seeding of alloying atoms at controlled depths and concentrations allows the subsequent epitaxial growth to proceed with high crystalline quality while achieving the desired high indium or aluminum concentration in the active layer, thus resolving the contradiction between emission wavelength range and device performance
Solution Approach 2:
The patent employs local quality by creating a depth-dependent concentration profile through ion implantation. The alloying atom concentration varies with depth, allowing different regions of the layer to have optimized properties for their specific functions while maintaining overall crystalline quality and achieving broad emission wavelength range with high device performance
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 enables the production of high-performance light-emitting devices with adjusted indium or aluminum concentrations, overcoming the limitations of crystalline quality degradation and accessing a broader emission spectrum.
Implementation Method 1
performing an ion implantation of indium or of aluminum into an upper portion of a first single-crystal gallium nitride layer, to make the upper portion of the first layer amorphous
Implementation Method 2
performing a solid phase recrystallization anneal of the upper surface of the first layer, resulting in transforming the upper portion of the first layer into a crystalline indium gallium nitride or aluminum gallium nitride layer
Implementation Method 3
performing a solid phase recrystallization anneal of the upper surface of the first layer
Implementation Method 4
deposition, by vapor phase epitaxy, on the upper surface of the first layer, of a light-emitting structure
Data Source
AI summary
A method of manufacturing an electronic device, including the successive steps of: a) performing an ion implantation of indium or of aluminum into an upper portion of a first single-crystal gallium nitride layer, to make the upper portion of the first layer amorphous and to preserve the crystal structure of a lower portion of the first layer; and b) performing a solid phase recrystallization anneal of the upper portion of the first layer, resulting in transforming the upper portion of the first layer into a crystalline indium gallium nitride or aluminum gallium nitride layer.