hBNC Graphene Transistor Channel for Stable Band Gap and Mobility
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Solution Overview
Problem
The implementation of 2D transistors on physical wafers faces challenges such as unstable band gap of channel material, leakage, molecular absorption, and carrier mobility degradation.
Innovation Solution
A method involving the formation and transfer of a hexagonal boron nitride carbon (hBNC) layer, comprising hBN flakes and a graphene layer, onto a wafer, utilizing a copper film with a single-crystalline structure as a substrate, to stabilize the band gap and enhance carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional 2D channel materials are used in transistors, then the device structure can be implemented, but the band gap becomes unstable and carrier mobility degrades
Solution Approach 1:
The patent uses a composite channel structure consisting of hexagonal boron nitride (hBN) and carbon (graphene) layers, forming hBNC material. This composite structure combines the wide band gap properties of hBN with the high carrier mobility of graphene, achieving both stable band gap and high carrier mobility that conventional single-material 2D channels cannot provide
Solution Approach 2:
The patent changes the material composition parameters by introducing controlled amounts of carbon into the hBN lattice to form hBNC. By adjusting the carbon concentration and distribution, the band gap and carrier mobility parameters are optimized simultaneously, resolving the contradiction between band gap stability and carrier mobility
2Length of moving object
If 2D channel materials are used, then atomic-scale thin channel can be achieved, but leakage and molecular absorption problems occur
Solution Approach 1:
The hBNC composite channel layer combines hBN's excellent insulating properties and chemical stability with graphene's atomic thickness. The hBN component provides barrier against leakage and molecular absorption, while the graphene component maintains atomic-scale thinness for high carrier mobility, solving the contradiction between thin channel dimension and harmful effects
3Ease of manufacture
If polycrystalline copper film is used as substrate, then deposition process is simpler, but the resulting hBNC layer has misaligned orientations and degraded performance
Solution Approach 1:
The patent performs preliminary thermal annealing treatment on the copper film substrate before depositing hBN and carbon layers. This preliminary action transforms the copper substrate into a single-crystalline structure with well-defined orientation, which then templates the hBNC layer to grow with aligned orientations, ensuring high manufacturing precision while maintaining process simplicity
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 hBNC layer achieves a stable band gap and high carrier mobility, resulting in excellent device performance for transistors, overcoming previous issues of instability and mobility degradation.
Implementation Method 1
utilizing a copper film with a single-crystalline structure as a substrate, to stabilize the band gap
Implementation Method 2
The hBNC layer achieves a stable band gap and high carrier mobility, resulting in excellent device performance for transistors
Data Source
AI summary
A transistor includes a channel layer, a gate stack, and source/drain regions. The channel layer includes a graphene layer and hexagonal boron nitride (hBN) flakes dispersed in the graphene layer. Orientations of the hBN flakes are substantially aligned. The gate stack is over the channel layer. The source/drain regions are aside the gate stack.