GaN Laminated Structure for High-Crystallinity Large-Area Substrates
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Solution Overview
Problem
The challenge is to form a gallium nitride film with high crystallinity on a large-area substrate, as conventional high-temperature deposition methods result in low crystallinity and difficulties in using large-area backplanes, especially with amorphous glass substrates that have low heat resistance.
Innovation Solution
A laminated structure is developed using a substrate with a surface arithmetic mean roughness less than 0.33 nm, where a gallium nitride film is formed by sputtering, optionally with an alignment layer and a protective layer, to achieve high crystallinity and c-axis orientation, allowing for the use of amorphous glass or resin substrates and increasing the productivity of LEDs and transistor backplanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gallium nitride film is formed on large-area substrate with low heat resistance, then productivity is improved, but surface unevenness inhibits crystal growth and reduces manufacturing precision
Solution Approach 1:
The substrate surface is pre-treated to achieve ultra-smoothness (Ra < 0.33 nm) before gallium nitride film deposition. This preliminary surface preparation ensures that even on large-area substrates, the surface uniformity required for high-crystallinity film growth is established in advance, eliminating the inhibiting effect of surface unevenness on crystal growth
Solution Approach 2:
The invention changes the critical parameter of substrate surface roughness from conventional values to ultra-low values (Ra < 0.33 nm). This parameter transformation enables the formation of high-crystallinity gallium nitride films on large-area substrates by creating surface conditions that promote uniform crystal growth across the entire substrate area
2Manufacturing precision
If conventional MOCVD or HVPE methods are used to form gallium nitride film, then film formation is achieved, but high temperature (800-1000°C) is required which is incompatible with low heat resistance substrates
Solution Approach 1:
The invention replaces the conventional MOCVD or HVPE deposition methods with a sputtering process. This substitution allows gallium nitride film formation at lower temperatures that are compatible with substrates having low heat resistance, while the ultra-smooth substrate surface (Ra < 0.33 nm) ensures that the sputtered film achieves high crystallinity despite the lower processing temperature
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 gallium nitride films with high crystallinity and c-axis orientation on large-area substrates, enhancing the productivity of LEDs and allowing for the manufacture of transistors on large-area backplanes with improved crystallinity and efficiency.
Implementation Method 1
an alignment layer having a c-axis orientation or a (111) orientation of a face-centered cubic structure, over the substrate, and a gallium nitride film on the alignment film
Implementation Method 2
deposited via sputtering
Data Source
AI summary
A laminated structure includes a substrate, and a gallium nitride film on the substrate. Further, a laminated structure includes a substrate, an alignment layer having a c-axis orientation or a (111) orientation of a face-centered cubic structure, over the substrate, and a gallium nitride film on the alignment film. Furthermore, a laminated structure includes a substrate, a protective layer on the substrate, an alignment layer having a c-axis orientation or a (111) orientation of a face-centered cubic structure, over the protective layer, and a gallium nitride film on the alignment film. A surface arithmetic mean roughness (Ra) of a surface of the substrate is less than 0.33 nm.