InGaN Layer Growth via Nitrogen-Rich Precursor Ratio
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Solution Overview
Problem
III/V semiconductor materials, such as InGaN, often suffer from defects like dislocations and strain relaxation issues due to lattice mismatch with substrates, leading to reduced crystalline quality and device performance.
Innovation Solution
The method involves growing InGaN and ternary III-nitride materials using a precursor gas mixture with a nitrogen precursor to Group III precursors ratio of at least 5,600, which reduces V-pit formation and lattice parameter mismatch, resulting in improved crystalline quality and reduced defect density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If III/V semiconductor materials are grown on substrates with lattice mismatch, then epitaxial growth can proceed, but strain relaxation and dislocation defects occur reducing crystalline quality
Solution Approach 1:
The patent applies parameter changes by precisely controlling the nitrogen precursor to Group III precursors ratio (maintaining it at least 5,600) and adjusting growth temperature and pressure parameters during epitaxial growth. This controlled parameter regime enables high-quality InGaN layer growth while minimizing strain accumulation and defect formation, directly resolving the contradiction between achieving sufficient layer thickness and maintaining crystalline quality
Solution Approach 2:
The patent employs segmentation by growing multiple alternating layers of InGaN and GaN with different lattice parameters. This layered structure allows strain to be managed incrementally across interfaces rather than accumulating in a single thick layer, enabling overall thicker structures to be grown while maintaining crystalline quality and reducing dislocation density
2Length of stationary object
If the layer thickness is increased beyond critical thickness, then more material is available for device fabrication, but strain relaxation causes dislocation formation and surface roughening
Solution Approach 1:
The patent segments the thick semiconductor structure into multiple alternating layers of InGaN and GaN, each thinner than the critical thickness for strain relaxation. This allows the overall structure to achieve the desired total thickness for device fabrication while each individual layer remains below the strain relaxation threshold, preventing dislocation formation and surface roughening
Solution Approach 2:
The patent performs preliminary strain management by alternating between InGaN layers (which accumulate strain) and GaN layers (which have different lattice parameters and can relieve strain). This preliminary action of strain compensation through alternating layers enables subsequent layers to be grown thicker without reaching the critical thickness for strain relaxation and defect formation
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 formation of InGaN and ternary III-nitride materials with smaller V-pits and reduced defects, enhancing the quality and performance of semiconductor devices by maintaining a higher crystalline integrity and reducing strain-related issues.
Implementation Method 1
The method involves growing InGaN and ternary III-nitride materials using a precursor gas mixture with a nitrogen precursor to Group III precursors ratio of at least 5,600
Implementation Method 2
III/V semiconductor materials may be fabricated by depositing, or 'growing,' a layer of III/V semiconductor material on an underlying substrate. The crystalline III/V semiconductor material may be grown epitaxially on the underlying substrate
Data Source
AI summary
Methods of forming ternary III-nitride materials include epitaxially growing ternary III-nitride material on a substrate in a chamber. The epitaxial growth includes providing a precursor gas mixture within the chamber that includes a relatively high ratio of a partial pressure of a nitrogen precursor to a partial pressure of one or more Group III precursors in the chamber. Due at least in part to the relatively high ratio, a layer of ternary III-nitride material may be grown to a high final thickness with small V-pit defects therein. Semiconductor structures including such ternary III-nitride material layers are fabricated using such methods.