GaN LED Buffer Layer Sputtering on Patterned Sapphire
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Solution Overview
Problem
Existing GaN based light emitting devices face challenges in achieving high light emission efficiency due to issues with buffer layer stability on sapphire substrates with uneven patterns, leading to reduced crystallinity and internal quantum efficiency.
Innovation Solution
A method involving the formation of a buffer layer using the sputtering method with a pivoted magnetron magnetic circuit on a sapphire substrate with an uneven convex or concave pattern, which enhances the growth of a GaN based semiconductor layer with improved crystallinity and light emission properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an uneven pattern is formed on a sapphire substrate to improve light emission efficiency, then light emission efficiency is improved, but buffer layer stability deteriorates
Solution Approach 1:
The patent applies local quality by creating an uneven pattern with convex portions on the sapphire substrate surface. This local structural modification changes the buffer layer formation characteristics specifically at the convex portions, enabling stable buffer layer growth only in these localized areas rather than uniformly across the entire substrate surface.
Solution Approach 2:
The patent employs preliminary action by pre-forming the uneven pattern structure on the sapphire substrate before depositing the buffer layer. This pre-structured substrate surface guides the subsequent buffer layer formation process, ensuring that the buffer layer naturally stabilizes on the convex portions without requiring additional stabilization steps.
2Loss of energy
If a buffer layer is formed on an uneven patterned substrate, then light emission efficiency improves, but manufacturing precision deteriorates
Solution Approach 1:
The convex portions create localized high-quality growth sites where the buffer layer forms with superior crystallinity and stability. This local quality approach ensures that even though the overall substrate is uneven, the critical buffer layer formation occurs with high precision at the convex regions.
Solution Approach 2:
The convex portions of the uneven pattern act as intermediary structures that mediate between the flat sapphire substrate and the buffer layer. These convex intermediaries provide a geometric template that facilitates precise buffer layer nucleation and growth, bridging the gap between the uneven substrate surface and the requirement for precise buffer layer 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 stabilizes the buffer layer formation, resulting in a light emitting device with enhanced light emission efficiency and properties, effectively addressing the limitations of previous methods.
Implementation Method 1
a method involving the formation of a buffer layer using the sputtering method with a pivoted magnetron magnetic circuit
Data Source
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AI summary
A method for producing a gallium nitride based compound semiconductor light emitting device which is excellent in terms of the light emitting properties and the light emission efficiency and a lamp is provided. In such a method for producing a gallium nitride based compound semiconductor light emitting device, which is a method for producing a GaN based semiconductor light emitting device having at least a buffer layer, an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer on a translucent substrate, on which an uneven pattern composed of a convex shape and a concave shape is formed, the buffer layer is formed by a sputtering method conducted in an apparatus having a pivoted magnetron magnetic circuit and the buffer layer contains AlN, ZnO, Mg, or Hf.