SiC Substrate Graphene Film Orientation for High Mobility
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Solution Overview
Problem
When manufacturing electronic devices using a graphene film as a conductive portion on a silicon carbide substrate, the mobility of the conductive portion often falls short of expected values, hindering high-speed device production.
Innovation Solution
A laminated body with a silicon carbide substrate and a graphene film where the graphene's atomic arrangement is oriented with respect to the substrate's atomic arrangement, featuring a region with a G′/G ratio of at least 1.2 in 10% or more of the exposed surface area, ensuring high mobility and reduced substrate non-graphene regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large-diameter supporting substrate is used to improve mass production efficiency, then productivity increases, but the region with no graphene film increases, worsening manufacturing precision
Solution Approach 1:
The patent changes the substrate material from conventional materials to silicon carbide (SiC), which enables direct growth of high-quality graphene films across large areas. This material parameter change allows maintaining large substrate diameters for mass production while achieving complete graphene coverage and high carrier mobility, thus resolving the contradiction between productivity and manufacturing precision
2Manufacturing precision
If the graphene film coverage is increased to improve manufacturing precision, then alignment precision improves, but the substrate cost and complexity increase
Solution Approach 1:
By changing the substrate material to silicon carbide and optimizing the growth conditions (temperature, pressure, gas flow), the patent achieves complete graphene film coverage directly on the substrate surface. This eliminates the need for additional graphene transfer processes and complex substrate structures, thereby improving manufacturing precision without increasing device complexity
3Speed
If the graphene film quality is improved to achieve high carrier mobility, then electronic device speed improves, but the production complexity and cost increase
Solution Approach 1:
The patent achieves high carrier mobility (>5000 cm²/Vs) by changing the substrate material to silicon carbide and optimizing growth parameters including temperature (1000-1500°C), pressure, and gas composition. This direct growth method on SiC substrates produces high-quality graphene with few defects, achieving high electron mobility without requiring complex post-processing or additional production steps
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 configuration stabilizes high mobility in electronic devices, facilitating mass production by minimizing non-graphene areas and achieving carrier mobilities of 5000 cm2/Vs or higher, thereby enhancing device speed and manufacturing efficiency.
Implementation Method 1
a graphene thin film grown by CVD (Chemical Vapor Deposition) is adhered to a supporting substrate
Implementation Method 2
a substrate composed of SiC (silicon carbide) is heated to separate Si atoms in order to convert a surface layer portion of the substrate into graphene
Data Source
AI summary
A laminated body includes: a substrate portion composed of silicon carbide; and a graphene film disposed on a first main surface of the substrate portion, the graphene film having an atomic arrangement oriented with respect to an atomic arrangement of the silicon carbide of the substrate portion. A region in which a value of G′/G in Raman spectrometry is not less than 1.2 is not less than 10% in an area ratio in an exposed surface of the graphene film, the exposed surface being a main surface of the graphene film opposite to the substrate portion.