Graphene Channel Width Control via Side Surface Growth
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Solution Overview
Problem
Forming graphene structures with a small width for transistors is challenging due to difficulties in shaping graphene on large areas and bonding it to electrodes, as existing methods like patterning or etching are inefficient and prone to errors.
Innovation Solution
A method involving the growth of graphene layers from exposed side surfaces of a growth layer using chemical vapor deposition (CVD), with alternately stacked growth and protective layers, allowing for the formation of graphene channels and electrodes with precise control over width and alignment, thereby enabling efficient integration of graphene devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If graphene is formed to have a small width by using patterning or etching method, then the graphene channel width is reduced to several nanometers, but it becomes difficult to form the graphene on a large area in a desired shape and difficult to bond the graphene to an electrode
Solution Approach 1:
Instead of patterning graphene to create narrow channels, the patent inverts the approach by growing narrow graphene channels directly from the side surfaces of vertically aligned nanotube arrays. This growth-based method naturally produces the desired narrow width without requiring subsequent patterning steps, thereby maintaining both precision and ease of manufacture on large areas
Solution Approach 2:
The patent transitions from two-dimensional patterning of graphene sheets to three-dimensional growth from vertical nanotube side surfaces. By utilizing the vertical dimension and growing graphene laterally from nanotube arrays, the method achieves precise narrow channel formation across large areas while simplifying the manufacturing process and improving electrode bonding capability
2Reliability
If graphene is formed to have a small width of about several nanometers, then semiconductor characteristics are achieved, but it may be difficult to bond the graphene to an electrode
Solution Approach 1:
The patent performs preliminary actions by vertically aligning nanotube arrays and forming metal layers on them before growing the graphene channels. This preliminary structuring creates well-defined growth sites and ensures that when graphene grows from the nanotube side surfaces, it will have proper electrical contact with the pre-positioned metal electrodes, thereby ensuring both semiconductor characteristics and ease of bonding
3Manufacturing precision
If conventional patterning or etching methods are used to form narrow graphene channels, then the channel width is reduced, but the process becomes complex and prone to errors
Solution Approach 1:
The patent employs self-service by utilizing the nanotube arrays as self-aligned templates that automatically define the position and width of the graphene channels. The graphene grows spontaneously from the nanotube side surfaces where metal catalysts are pre-deposited, eliminating the need for complex external patterning processes and reducing manufacturing complexity while maintaining high precision
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
Enables the formation of graphene devices with very small width channels and electrodes, facilitating stable and efficient electrical connections, reducing bonding errors, and allowing for large-area graphene formation, suitable for various electronic and optoelectronic applications.
Implementation Method 1
The at least one graphene layer may be grown from the exposed side surfaces of the at least one growth layer by using a chemical vapor deposition (CVD) method.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A graphene structure and a method of manufacturing the graphene structure, and a graphene device and a method of manufacturing the graphene device. The graphene structure includes a substrate; a growth layer disposed on the substrate and having exposed side surfaces; and a graphene layer disposed on the side surfaces of the growth layer. A growth layer 120 and a protective layer 130 are sequentially formed on a substrate 110. The growth layer 120 is a layer from which a graphene layer 140 grows, and may be formed of for example, metal or germanium (Ge). The growth layer 120 may have a thickness of, for example, about several nanometers. As will be described later, the thickness of the growth layer 120 determines a width W of the graphene layer 140. Then, the protective layer 130 is formed on an upper surface of the growth layer 120. A groove 150 is formed in the protective layer 130 and the growth layer 120. The groove 150 is formed in a predetermined shape by sequentially etching the protective layer 130 and the growth layer 120. The groove 150 exposes side surfaces of the protective layer 130 and the growth layer 120 and an upper surface of the substrate 110. The groove 150 may be formed by etching the protective layer 130 and the growth layer 120 by using an etching mask until the upper surface of the substrate 110 is exposed. FIG. 3A is a perspective view showing that the graphene layer 140 is grown from the side surfaces of the growth layer 120.