Heterogeneous Substrate for Nitride Semiconductor Flat Surface
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Solution Overview
Problem
The challenge is to create a heterogeneous substrate with a non-polar or semi-polar nitride layer on a non-polar or semi-polar plane that has a flat surface and reduced internal defects, which is essential for improving the yield and performance of nitride-based semiconductor devices.
Innovation Solution
A substrate with a base substrate, nucleation layer, first buffer layer grown faster vertically, lateral growth layer grown faster laterally, and a second buffer layer, optionally including a silicon nitride layer with holes to promote lateral crystal growth, is used to form a high-quality non-polar or semi-polar nitride layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-polar or semi-polar nitride layer is formed on a non-polar or semi-polar plane, then quantum efficiency is improved and internal electric field problems are overcome, but the surface becomes rough and internal defects increase
Solution Approach 1:
The patent divides the nitride layer formation into multiple segments: a nucleation layer formed first on the non-polar or semi-polar plane, followed by a separate flatting layer that planarizes the surface. This segmentation allows the nucleation layer to provide good crystal quality and quantum efficiency while the flatting layer independently addresses the surface flatness issue, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent introduces a flatting layer as an intermediary between the nucleation layer and subsequent device layers. This intermediate layer serves as a mediator that absorbs the surface roughness from the non-polar/semi-polar nitride layer while providing a flat surface for subsequent processing, thus resolving the surface flatness problem without compromising the underlying crystal quality and quantum efficiency.
2Reliability
If a non-polar or semi-polar nitride layer is formed on a non-polar or semi-polar plane, then polarization-related problems are solved, but the number of internal defects increases
Solution Approach 1:
The patent segments the layer structure into a nucleation layer with good crystal quality formed on the non-polar or semi-polar plane, and a separate flatting layer that reduces surface roughness. This segmentation isolates the polarization benefits in the nucleation layer while the flatting layer addresses defect reduction, allowing the device to achieve both good polarization performance and reduced internal defects.
Solution Approach 2:
The flatting layer acts as an intermediary that reduces internal defects by planarizing the surface and providing a stable foundation for subsequent layers. This intermediate layer filters out the harmful surface roughness and defect propagation while preserving the polarization advantages of the underlying non-polar or semi-polar nitride structure.
3Manufacturing precision
If multiple buffer layers with different growth rates are used, then surface flatness and crystal quality are improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating buffer layers with spatially varying growth characteristics. The nucleation layer has specific growth properties optimized for crystal quality on the non-polar/semi-polar plane, while the flatting layer has different growth properties optimized for surface planarization. This local differentiation of growth qualities allows each layer to perform its specific function efficiently, achieving high surface flatness while managing complexity through functional specialization.
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 a nitride layer with a flat surface and minimal internal defects, enhancing the crystallinity and performance of nitride-based semiconductor devices, such as light-emitting elements and High Electron Mobility Transistors.
Implementation Method 1
The first buffer layer is formed on the nucleation layer and is grown faster in a vertical direction than in a lateral direction
Implementation Method 2
The lateral growth layer is formed on the first buffer layer and is grown faster in the lateral direction than in the vertical direction
Implementation Method 3
crystals beneath the silicon nitride layer are grown through the holes of the silicon nitride layer to cover the silicon nitride layer
Data Source
AI summary
Provided are a heterogeneous substrate, a nitride-based semiconductor device using the same, and a manufacturing method thereof to form a high-quality non-polar or semi-polar nitride layer on a non-polar or semi-polar plane of the heterogeneous substrate by adjusting a crystal growth mode. A base substrate having one of a non-polar plane and a semi-polar plane is prepared, and a nitride-based nucleation layer is formed on the plane of the base substrate. A first buffer layer is grown faster in the vertical direction than in the lateral direction on the nucleation layer. A lateral growth layer is grown faster in the lateral direction than in the vertical direction on the first buffer layer. A second buffer layer is formed on the lateral growth layer. A silicon nitride layer having a plurality of holes may be formed between the lateral growth layer on the first buffer layer and the second buffer layer.