GaN Semiconductor Crystallinity via Oxygen Control
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Solution Overview
Problem
Existing methods for manufacturing n-down type semiconductor devices face challenges in achieving high crystallinity and bonding characteristics due to surface roughness of n-type semiconductor layers and the introduction of etching stop layers, which degrade the crystallinity of GaN layers and hinder efficient bonding with supporting substrates.
Innovation Solution
A semiconductor device with a conductive-layer-neighboring group III nitride semiconductor layer having a dislocation density of at most 1×10^7 cm^-2 and oxygen concentration of at most 5×10^18 cm^-3, grown using a method that involves forming a conductive layer on a pre-prepared composite substrate and joining it to a supporting substrate, ensuring high crystallinity and bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an etching stop layer is interposed between the underlying layer and the semiconductor layer, then etching damage to the semiconductor layer is reduced, but the crystallinity of the GaN layers deteriorates
Solution Approach 1:
The invention removes the etching stop layer from the structure and instead applies etching stop conditions to the buffer layer itself by controlling its thickness and composition. This extracts the harmful intermediate layer while preserving the crystallinity of the GaN layers, as the buffer layer can serve both as a growth foundation and an etching termination layer when properly designed.
Solution Approach 2:
The buffer layer is given multiple functions: it serves as a growth foundation for the GaN layers, acts as an etching stop layer through controlled thickness and composition, and maintains crystallinity. This multi-functional approach eliminates the need for a separate etching stop layer while achieving the same protective effect.
2Illumination intensity
If the underlying substrate is separated from the n type semiconductor layer, then light extraction efficiency is enhanced, but the n type semiconductor layer surface becomes rough and bonding capability deteriorates
Solution Approach 1:
The invention applies different surface treatments to different regions: the light-emitting surface receives rugged patterning for enhanced light extraction, while the bonding surface maintains high flatness and low defect density through controlled separation and protection methods, enabling both functions to coexist.
Solution Approach 2:
The buffer layer is designed with specific thickness and composition before separation to prevent surface roughening during the separation process. This preliminary preparation ensures that when the substrate is separated, the n-type layer surface remains smooth and suitable for bonding.
3Ease of manufacture
If a buffer layer is used to join the group III nitride semiconductor layer to the supporting substrate, then laser lift-off is eased, but the crystallinity and bonding characteristic of the semiconductor layer deteriorates
Solution Approach 1:
The invention removes the separate buffer layer that causes crystallinity degradation and instead achieves laser lift-off functionality through controlled interface conditions between the semiconductor layer and supporting substrate, eliminating the harmful intermediate layer while maintaining high crystallinity.
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
The approach enables the production of n-down type semiconductor devices with high crystallinity and improved bonding characteristics to supporting substrates, enhancing the performance and reliability of the semiconductor devices.
Implementation Method 1
growing, on the first group III nitride semiconductor layer of the first composite substrate, at least one second group III nitride semiconductor layer
Data Source
AI summary
A semiconductor device includes a supporting substrate, a conductive layer placed on the supporting substrate, and at least one group III nitride semiconductor layer placed on the conductive layer. Of the group III nitride semiconductor layers, a conductive-layer-neighboring group III nitride semiconductor layer has n type conductivity, dislocation density of at most 1×107 cm−2, and oxygen concentration of at most 5×1018 cm−3. Thus, an n-down type device having a semiconductor layer of high crystallinity can be provided.