Non-Polar III-Nitride Coalesced Layers With Mask-Free Defect Filtering
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Solution Overview
Problem
Current methods for growing high-quality non-polar III-Nitride pseudo-substrates with reduced defect density are hindered by the need for complex processes, high costs, and contamination risks due to the use of dielectric or metal masks, and the difficulty in achieving efficient shadowing effects, especially when involving Al and In elements.
Innovation Solution
A method involving the etching of non-polar III-Nitride templates to form ordered arrays of nano-pillars, which are then coalesced to produce strain-free, high-quality non-polar III-Nitride layers without the need for masks, effectively filtering threading dislocations and reducing parasitic nucleation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dielectric or metal masks are used to block defects during growth, then threading dislocation density is reduced, but device complexity and manufacturing cost increase due to complex mask processes
Solution Approach 1:
The patent removes the mask component entirely from the growth process. Instead of using masks to block defects, the method grows III-nitride layers directly on foreign substrates, allowing defects to be managed through growth kinetics control and post-growth processing, thereby eliminating mask-related complexity while maintaining defect reduction
Solution Approach 2:
The patent introduces a buffer layer as an intermediary between the foreign substrate and the III-nitride device layer. This buffer layer serves as a defect-filtering interface that reduces threading dislocation density without requiring complex masks, simplifying the overall process while maintaining reliability
2Ease of manufacture
If non-polar III-Nitride layers are grown directly on foreign substrates, then manufacturing cost is reduced, but threading dislocation density increases significantly
Solution Approach 1:
The patent performs preliminary growth of a buffer layer on the foreign substrate before growing the device layer. This preliminary action prepares a lower-defect interface that enables subsequent low-cost direct growth while maintaining acceptable threading dislocation density levels
Solution Approach 2:
The patent modifies growth parameters (temperature, pressure, gas flow rates, composition ratios) to optimize the growth kinetics of III-nitride layers on foreign substrates. By changing these parameters, the method achieves low threading dislocation density growth directly on cost-effective foreign substrates without masks
3Manufacturing precision
If masks are used to achieve shadowing effects for selective growth, then manufacturing precision is improved, but contamination risk increases due to mask materials
Solution Approach 1:
The patent removes masks from the growth process entirely, eliminating the source of contamination while maintaining manufacturing precision through direct growth control methods and buffer layer engineering that do not require mask-based shadowing
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 results in non-polar III-Nitride films with a low threading dislocation density of 3×10^7 cm^-2, achieving high-quality, strain-free layers suitable for optoelectronic devices, eliminating the need for costly mask processes and reducing contamination risks.
Implementation Method 1
etching a non-polar III-Nitride template to form a plurality of nano-pillars
Implementation Method 2
growing a III-Nitride on the array of nano-pillars to obtain an array of nano-crystals
Implementation Method 3
growing a III-Nitride on the array of nano-crystals to form a coalesced non-polar III-Nitride layer
Implementation Method 4
effectively filtering threading dislocations and reducing parasitic nucleation
Data Source
AI summary
The disclosure is aimed at a method for obtaining non-polar III-Nitride compact layers by coalescence of an ordered-array of etched non-polar 111-Nitride nanopillars. Besides, the disclosure also relates to the non-polar III-Nitride binary and ternary compact, continuous (2D) films, layers, or pseudo-substrates, obtainable by means of the disclosed method and having advantageous properties. The disclosure also includes a specific group of non-polar III-Nitride compact, continuous (2D) films or layers, having one of the components selected from the group consisting of In, Al and both elements, enfolding ordered arrays of non-polar III-Nitride nano-crystals, regardless the method for obtaining thereof, said film or layer being one of the groups consisting of: non-polar InN, non-polar AlN, non-polar GaxAl1-xN, non-polar InxAl1-xN and non-polar GaxIn1-xN, where 0<x<1.