Graphene FET Slit Segmentation for ON/OFF Ratio
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Solution Overview
Problem
Graphene-based field effect transistors face a low ON/OFF ratio of operation currents due to graphene's zero band gap energy structure, allowing high current flow even in the OFF state without gate voltage, which limits their performance as high-speed switching devices.
Innovation Solution
Incorporating a slit in the graphene channel layer filled with a potential barrier material, such as undoped silicon, to induce Fowler-Nordheim tunneling when a gate voltage is applied, enhancing the ON/OFF ratio by controlling electron movement between areas of the graphene channel layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If graphene is used as channel layer, then high electric conductivity and high-speed switching are achieved, but ON/OFF ratio remains low due to zero band gap
Solution Approach 1:
The graphene channel layer is segmented by introducing slits that divide the continuous channel into separate regions. These slits are filled with potential barrier materials (such as undoped silicon) to create localized potential barriers that control electron transport, enabling the channel to be switched between conducting and blocking states while maintaining high-speed operation.
Solution Approach 2:
Potential barrier materials (e.g., undoped silicon) are introduced as intermediary substances within the slits of the graphene channel layer. These intermediary materials create localized potential barriers that mediate electron transport through the graphene, enabling control of current flow and achieving high ON/OFF ratios while preserving the high-speed characteristics of graphene.
2Reliability
If potential barrier material is introduced in slits, then ON/OFF ratio is improved through controlled tunneling, but device structure becomes more complex
Solution Approach 1:
The channel layer is segmented by creating slits that are subsequently filled with potential barrier materials. This segmentation approach allows the complex functionality of controlled electron tunneling to be achieved through localized modifications rather than complicating the entire channel structure, thereby improving ON/OFF ratio while managing device complexity.
3Reliability
If slit width is optimized for F-N tunneling, then electron transport control is improved, but manufacturing precision requirements increase
Solution Approach 1:
The slit width parameter is optimized to enable Fowler-Nordheim tunneling of electrons through the potential barrier materials. By carefully controlling the slit width within specific ranges, the device achieves effective electron transport control for high ON/OFF ratios. The patent acknowledges that this parameter optimization necessitates high manufacturing precision to ensure consistent device performance.
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 solution effectively increases the ON/OFF ratio of operation currents in graphene-based field effect transistors by enabling controlled electron tunneling through the potential barrier, improving their performance as high-speed switching devices.
Implementation Method 1
The potential barrier material may be configured to induce Fowler-Nordheim (F-N) tunneling through the graphene channel layer when a gate voltage is applied to the gate electrode.
Data Source
AI summary
According to example embodiments, a field effect transistor includes a graphene channel layer on a substrate. The graphene channel layer defines a slit. A source electrode and a drain electrode are spaced apart from each other and arranged to apply voltages to the graphene channel layer. A gate insulation layer is between the graphene channel layer and a gate electrode.