Cubic Silicon Carbide Epitaxy with Trenched Transition Surfaces
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Solution Overview
Problem
Current methods for forming high-quality, low-defect density cubic silicon carbide (3C-SiC) are economically infeasible and unable to produce material with improved electrical performance.
Innovation Solution
A method involving a step-controlled epitaxy technique is used to form a layer of α-SiC on a base substrate with an angled growth surface, followed by the formation of a β-SiC layer, utilizing trenches to create a transitional surface that facilitates the growth of defect-free 3C-SiC, allowing for the production of monocrystalline films in a cost-effective manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If current methods are used to form 3C-SiC, then material can be produced, but the production is economically infeasible and results in high defect density
Solution Approach 1:
The patent divides the growth process into distinct stages: forming trenches in the substrate, epitaxially growing α-SiC layers in the trenches, and then growing β-SiC layers on top. This segmentation allows each stage to be optimized independently, achieving low defect density while maintaining economic feasibility through controlled, stepwise growth rather than attempting to produce bulk 3C-SiC in one step.
Solution Approach 2:
The patent applies different crystal structures (α-SiC and β-SiC) to different regions and stages of the device structure. The α-SiC is grown in the trench regions where mechanical support and defect confinement are needed, while β-SiC is grown in the active device regions where electrical performance is critical. This local differentiation allows each material to perform its optimal function.
2Reliability
If current methods are used to form 3C-SiC, then material can be produced, but electrical performance is not improved
Solution Approach 1:
The patent performs preliminary actions by first forming the trench structure and growing the α-SiC layer before attempting to grow the final β-SiC layer. This preliminary structuring creates a template that guides the subsequent growth of high-quality 3C-SiC, ensuring good electrical performance is achieved in the active regions while the overall process remains manufacturable.
Solution Approach 2:
The α-SiC layer grown in the trenches acts as an intermediary structure that facilitates the growth of high-quality β-SiC layers. This intermediate layer provides a controlled interface and stress management mechanism that enables subsequent growth of electrically superior 3C-SiC material without requiring economically infeasible direct growth methods.
3Manufacturing precision
If high quality 3C-SiC is produced, then electrical performance improves, but production cost becomes prohibitive
Solution Approach 1:
By segmenting the growth into trench-based α-SiC regions and planar β-SiC regions, the patent achieves high material quality only where needed (in the active device areas) rather than requiring expensive processing of entire bulk substrates. This selective quality approach reduces overall production costs while maintaining high performance in critical regions.
Solution Approach 2:
The patent changes the crystal structure parameter from uniform α-SiC or 4H-SiC to a heterostructure combining α-SiC and β-SiC layers. This parameter change enables the system to achieve superior electrical characteristics in the β-SiC regions while the α-SiC regions provide structural support at lower cost, optimizing the overall cost-performance ratio.
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 cost-effective production of substantially defect-free 3C-SiC films with improved electrical characteristics, suitable for forming active device regions in semiconductor devices.
Implementation Method 1
epitaxially forming a first SiC layer on the growth surface of the base substrate by a step-controlled epitaxy technique
Implementation Method 2
forming first and second trenches in the base substrate that extend from the growth surface into the base substrate, epitaxially forming a first SiC layer on the growth surface of the base substrate by a step-controlled epitaxy technique, and epitaxially forming a second SiC layer on the first SiC layer, wherein the first SiC layer is a layer of α-SiC, and wherein the second SiC layer is a layer of β-SiC
Data Source
AI summary
A method of forming a semiconductor device includes providing a base substrate comprising SiC and a growth surface extending along a plane that is angled relative to a first crystallographic plane of the SiC from the base substrate, forming first and second trenches in the base substrate that extend from the growth surface into the base substrate, epitaxially forming a first SiC layer on the growth surface of the base substrate by a step-controlled epitaxy technique, and epitaxially forming a second SiC layer on the first SiC layer, wherein the first SiC layer is a layer of α-SiC, and wherein the second SiC layer is a layer of β-SiC.