GaN Substrate Defect Dispersion Suppression via Intermediate Layer
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Solution Overview
Problem
Nitride semiconductor layers grown on heterogeneous substrates often have high crystal defects, limiting their suitability for high-current density devices, and large-area semi-polar or non-polar substrates are difficult to produce due to defects and off-angle variations, which affects the quality and yield of semiconductor devices.
Innovation Solution
A method involving the growth of a gallium nitride substrate using hydride vapor phase epitaxy, followed by slicing, and then depositing a gallium nitride-based defect dispersion suppressing layer using metal organic chemical vapor deposition, grown at specific temperatures and pressures to control defect distribution, allowing for the growth of high-quality nitride semiconductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nitride semiconductor layer is grown on a heterogeneous substrate such as sapphire, then substrate availability is improved, but crystal defect density increases
Solution Approach 1:
The patent introduces an intermediate substrate structure: a bulk gallium nitride single crystal grown on sapphire that is then sliced to create a homogeneous gallium nitride substrate. This intermediate step acts as a mediator between the heterogeneous sapphire substrate and the nitride semiconductor layer, eliminating direct heteroepitaxial defects while maintaining substrate availability.
2Area of stationary object
If a bulk gallium nitride single crystal is grown and sliced to create a large substrate, then substrate size is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the substrate manufacturing process into distinct stages: (1) growing bulk gallium nitride single crystals on sapphire substrates, (2) slicing the grown crystals into thin wafers to create homogeneous gallium nitride substrates, and (3) growing semiconductor layers on these substrates. This segmentation allows each stage to be optimized independently, achieving large substrate sizes while managing manufacturing complexity.
3Area of stationary object
If seed substrates are arranged to create a large-area gallium nitride substrate, then substrate area is improved, but defect density increases due to boundary regions
Solution Approach 1:
The patent extracts and eliminates the problematic boundary regions between seed substrates by using a different approach: growing bulk single crystals that naturally form continuous, defect-free large-area substrates when sliced. This removes the boundary defect issue inherent in seed-substrate assembly methods while maintaining large substrate area.
4Adaptability or versatility
If non-polar or semi-polar substrates are prepared using seed substrates, then substrate type versatility is improved, but off-angle distribution increases
Solution Approach 1:
The patent changes the fundamental parameter of substrate preparation from mechanical assembly of seed substrates to controlled crystal growth. By adjusting growth parameters during bulk crystal formation, the method achieves precise control over crystal orientation and eliminates off-angle distribution while maintaining versatility in producing non-polar and semi-polar substrate types.
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 effectively suppresses defect dispersion in nitride semiconductor layers, enabling the production of high-yield, mass-producible non-polar or semi-polar semiconductor devices with improved crystal quality and reduced defect regions.
Implementation Method 1
growing a gallium nitride crystal on seed substrates using hydride vapor phase epitaxy
Implementation Method 2
growing a gallium nitride crystal on seed substrates using hydride vapor phase epitaxy
Implementation Method 3
growing a gallium nitride-based defect dispersion suppressing layer on the gallium nitride substrate formed in step (a) using metal organic chemical vapor deposition
Data Source
Figure 1(a)~2
Figure 3(a)~4(b)
Figure 5(a)~6
AI summary
Exemplary embodiments of the present invention provide a method of growing a nitride semiconductor layer including growing a gallium nitride-based defect dispersion suppressing layer on a gallium nitride substrate including non-defect regions and a defect region disposed between the non-defect regions, and growing a gallium nitride semiconductor layer on the defect dispersion suppressing layer.