AlGaInN-GaInN Stacked Body for Nitride Semiconductor Dislocation Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nitride semiconductor devices, such as LED and HEMT, face efficiency limitations due to high density threading dislocations caused by lattice mismatch with GaN crystal, leading to suboptimal performance in semiconductor light emitting devices.
Innovation Solution
A semiconductor device structure is developed with a first and second stacked body, including AlGaInN and GaInN layers alternately stacked, and a light emitting unit with a well layer, where the first stacked body has a depression embedding part of the light emitting unit and the second layer, optimizing crystal growth conditions to reduce dislocation impact and enhance light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitride semiconductor devices are used with GaN crystal, then the device structure can be formed, but high density threading dislocations occur due to lattice mismatch, reducing device efficiency
Solution Approach 1:
The patent divides the crystal structure into multiple segments: a GaN-based semiconductor layer is segmented into multiple quantum wells and barrier layers, and a stacked body with alternating high-In and low-In GaInN layers is introduced. This segmentation allows progressive strain relaxation and dislocation filtering, reducing threading dislocation density while maintaining device functionality.
Solution Approach 2:
The patent introduces an intermediary stacked body consisting of alternating high-In GaInN and low-In GaInN layers between the GaN-based semiconductor layer and the active region. This intermediary structure acts as a buffer that gradually transitions the lattice mismatch, filtering threading dislocations before they reach the active region while maintaining electrical functionality.
2Reliability
If the number of GaInN layers is increased to reduce dislocation effects, then device performance improves, but the device structure becomes more complex
Solution Approach 1:
The patent applies local quality by creating regions with different In compositions within the stacked body. High-In GaInN layers are positioned to provide strain relaxation and dislocation filtering, while low-In GaInN layers maintain structural integrity and electrical continuity. This localized composition variation optimizes dislocation management without requiring uniform complexity throughout the entire structure.
Solution Approach 2:
The patent implements periodic action through the alternating stacking of high-In and low-In GaInN layers. This periodic structure creates a regular pattern that systematically manages strain and dislocations throughout the crystal growth direction, providing consistent dislocation filtering while maintaining a manageable structural repetition that simplifies fabrication control.
3Reliability
If AlGaInN and GaInN layers are alternately stacked to improve surface flatness and reduce dislocations, then light emission efficiency increases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent utilizes parameter changes by systematically varying the In composition between high-In and low-In GaInN layers, as well as adjusting layer thicknesses. These parameter variations are optimized to control strain accumulation, promote surface flatness, and filter dislocations. By controlling composition and thickness parameters, the patent achieves improved light emission efficiency while maintaining manufacturability through established MOCVD or MBE growth techniques.
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 structure improves light emission efficiency and surface flatness, reducing dislocation effects and increasing the number of GaInN layers, resulting in enhanced semiconductor device performance and yield.
Implementation Method 1
the characteristics of such nitride semiconductor devices are restricted by high density threading dislocations due to lattice mismatch with the GaN crystal
Implementation Method 2
The first stacked body has a depression provided in a first surface. A part of the light emitting unit is embedded in at least a part of the depression
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first layer of n-type including a nitride semiconductor, a second layer of p-type including a nitride semiconductor, a light emitting unit, and a first stacked body. The light emitting unit is provided between the first and second layers. The first stacked body is provided between the first layer and the light emitting unit. The first stacked body includes a plurality of third layers including AlGaInN, and a plurality of fourth layers alternately stacked with the third layers and including GaInN. The first stacked body has a first surface facing the light emitting unit. The first stacked body has a depression provided in the first surface. A part of the light emitting unit is embedded in a part of the depression. A part of the second layer is disposed on the part of the light emitting unit.