Boron-Nitrogen Doped Graphene Transistor Band Gap
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Solution Overview
Problem
Graphene's zero-gap semiconductor nature makes it difficult to apply as a channel in field-effect transistors due to high off-current and small ON-OFF ratio, requiring the formation of a band gap, which is challenging to achieve, especially at nanoscale dimensions and with armchair edge patterning.
Innovation Solution
Graphene is substituted with boron and nitrogen atoms to create a band gap, using chemical vapor deposition with borazine or ammonia borane as precursors, maintaining the carbon structure's stability and allowing for controlled band gap formation through precise doping densities of B and N atoms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If graphene is used as a channel in field-effect transistors, then high electron mobility is achieved, but the zero-gap semiconductor nature causes very large off-current and very small ON-OFF ratio
Solution Approach 1:
The patent changes the chemical composition parameters of graphene by substituting carbon atoms with boron and nitrogen atoms. This substitution modifies the electronic band structure, opening a band gap while preserving the sp2 hybridized carbon network that enables high electron mobility. The controlled doping ratio allows simultaneous optimization of mobility and ON-OFF ratio.
Solution Approach 2:
The patent creates a composite material by introducing heteroatoms (boron and nitrogen) into the graphene lattice. This forms a boron-nitrogen-doped graphene composite that combines the high mobility characteristics of graphene with the band gap properties needed for transistor operation, achieving both high ON-OFF ratio and maintained mobility.
2Reliability
If a band gap is formed in graphene by reducing channel width below 10 nm with armchair edges, then a band gap is achieved, but it becomes difficult to pattern the channel width and edges
Solution Approach 1:
Instead of changing the physical dimensions (channel width) to achieve band gap, the patent changes the chemical composition by doping with boron and nitrogen. This allows band gap formation through chemical modification rather than geometric confinement, avoiding the need for sub-10 nm patterning while still achieving the desired electronic properties.
Solution Approach 2:
The patent replaces the mechanical/geometric approach (reducing channel width and shaping edges) with a chemical approach (atom substitution). This substitution method achieves band gap formation through chemical bonding modifications rather than physical dimension reduction, thereby avoiding the manufacturing precision challenges of nanoscale patterning.
3Reliability
If carbon atoms in graphene are substituted with boron and nitrogen atoms, then a band gap is formed, but the structural stability of graphene must be maintained
Solution Approach 1:
The patent applies local quality by substituting only specific portions of carbon atoms with boron and nitrogen atoms rather than complete replacement. This localized substitution (1-20% doping ratio) creates the necessary band gap while preserving the overall graphene lattice structure and its inherent stability. The majority of carbon atoms maintain the sp2 hybridized network.
Solution Approach 2:
The patent carefully controls the doping ratio parameter, substituting boron and nitrogen atoms at ratios between 1% to 20% of total carbon atoms. This parameter optimization ensures sufficient band gap formation while maintaining structural stability. The balanced substitution ratio prevents lattice distortion and preserves the hexagonal honeycomb structure.
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
The substitution of boron and nitrogen in graphene enables the formation of a band gap, improving the ON-OFF ratio and gate controllability of field-effect transistors, allowing for efficient operation as a channel, while maintaining the unique characteristics of graphene.
Implementation Method 1
graphene including a structure of carbon (C) atoms partially substituted with boron (B) atoms and nitrogen (N) atoms, wherein the graphene has a band gap
Implementation Method 2
there is provided a method of fabricating graphene by performing a chemical vapor deposition (CVD) method using borazine or ammonia borane as a boron nitride (B-N) precursor
Data Source
AI summary
Graphene, a method of fabricating the same, and a transistor having the graphene are provided, the graphene includes a structure of carbon (C) atoms partially substituted with boron (B) atoms and nitrogen (N) atoms. The graphene has a band gap. The graphene substituted with boron and nitrogen may be used as a channel of a field effect transistor. The graphene may be formed by performing chemical vapor deposition (CVD) method using borazine or ammonia borane as a boron nitride (B-N) precursor.