Nitride Semiconductor Template Buffer Layer Thickness Control
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Solution Overview
Problem
The use of unevenly processed sapphire substrates in nitride semiconductor templates can lead to surface pits due to uneven buffer layer growth, which obstructs device operation and reduces light extraction efficiency.
Innovation Solution
A method for manufacturing a nitride semiconductor template involving the growth of a buffer layer with a thickness between 10 nm and 330 nm on a sapphire substrate with conical or pyramidal projections, and a nitride semiconductor layer, using techniques like HVPE or MOVPE, to suppress the formation of surface pits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sapphire substrate with conical or pyramidal projections is used to improve light extraction efficiency and reduce dislocations, then the crystallinity of the nitride semiconductor layer is improved, but surface pits occur due to uneven buffer layer growth at the projection peaks
Solution Approach 1:
The invention changes the critical parameter of buffer layer thickness to resolve the contradiction. By controlling the buffer layer thickness to be equal to or less than the peak height of the projections (within 10-330 nm range), the buffer layer covers the projection peaks without forming sharp points, thereby preventing inversion domain formation and surface pit generation while maintaining the dislocation reduction effect of the uneven substrate
Solution Approach 2:
The invention applies preliminary action by forming the buffer layer with controlled thickness before growing the nitride semiconductor layer. This preliminary buffer layer formation prevents the formation of harmful sharp points at projection peaks, thereby preventing inversion domain formation in advance before the nitride semiconductor layer is grown
2Shape
If the buffer layer is grown thicker to cover the projections completely, then surface smoothness is improved, but inversion domains form at the projection peaks causing surface pits
Solution Approach 1:
The invention optimizes the buffer layer thickness parameter to a specific range (equal to or less than peak height, 10-330 nm) that prevents inversion domain formation. This parameter optimization shows that complete surface coverage is not necessary for smoothness, and the controlled thickness prevents the formation of sharp points that cause inversion domains
Solution Approach 2:
The invention uses the projection pattern as a template to guide buffer layer formation. By controlling the buffer layer thickness to match the projection peak height, the buffer layer replicates the projection topology without forming harmful sharp points, achieving surface smoothness while preventing inversion domains
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 effectively reduces the occurrence of surface pits and improves the crystallinity and light extraction efficiency of the nitride semiconductor template, enhancing the performance of light-emitting elements.
Implementation Method 1
growing and forming a buffer layer in a thickness of not more than a peak width of a projection and in a thickness of not less than 10 nm and not more than 330 nm on a sapphire substrate
Implementation Method 2
growing and forming a nitride semiconductor layer on the buffer layer
Data Source
AI summary
There is provided a method for manufacturing a nitride semiconductor template, including the steps of: growing and forming a buffer layer in a thickness of not more than a peak width of a projection and in a thickness of not less than 10 nm and not more than 330 nm on a sapphire substrate formed by arranging conical or pyramidal projections on its surface in a lattice pattern; and growing and forming a nitride semiconductor layer on the buffer layer.