Graphene Contact Layout With Dual-Oxide Insulation Alignment
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Solution Overview
Problem
Conventional methods for manufacturing graphene-based solid-state devices, such as GFETs, face challenges due to complex manufacturing processes and inaccurate alignment of source and drain contacts, which can lead to imperfections in the graphene layer affecting device performance.
Innovation Solution
The method involves fabricating graphene-based solid-state devices with at least two top contacts in a single lithographic step and using different oxide dielectric materials for insulation, ensuring high accuracy in alignment and minimizing etch rate differences between materials to prevent imperfections in the graphene layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If source and drain contacts are manufactured in separate lithographic and metallization steps, then the manufacturing process can be completed, but the alignment accuracy between contacts deteriorates and device complexity increases
Solution Approach 1:
The patent combines the fabrication of source and drain contacts into a single lithographic step and single metallization step, creating a unified contact structure. This merging approach directly improves alignment accuracy between contacts while reducing the overall complexity of the manufacturing process by eliminating multiple sequential steps
2Reliability
If conventional passivation materials are used on source and drain contacts, then current leakage is reduced, but imperfections in the graphene layer affect device performance
Solution Approach 1:
The patent extracts the problematic interaction between passivation materials and graphene layer imperfections by redesigning the contact structure to avoid the need for conventional passivation approaches that exacerbate graphene defects. The unified contact fabrication method reduces stress and damage to the graphene layer while maintaining effective current leakage control
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 approach results in a more accurate and reliable fabrication process with improved device performance by reducing current leakage and enhancing the sensitivity and responsivity of graphene-based sensors and photodetectors.
Implementation Method 1
applying a lithographic process to define at least two contact areas in the graphene layer
Implementation Method 2
depositing one metallic contact on each one of the at least two defined contact areas of the graphene layer
Implementation Method 3
The material for one of the insulations (i.e. insulation for gate contact when the device is a GFET) is selected to be mutually exclusive with the material for other insulations (i.e. insulation for the top contacts, such as source and drain contacts when the device is a GFET). The two selected materials present good etch selectivity between them.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A method of fabricating a graphene-based solid-state device, the method comprising: disposing a layer of an electric conductive material (102) on a substrate (101); depositing a first layer of an insulating material (103) on the layer of an electric conductive material (102), the first layer of an insulating material (103) being made of a first oxide dielectric material; patterning the first layer of an insulating material (103) to expose at least a portion of the layer of an electric conductive material (102); disposing a graphene layer (105) on the first layer of an insulating material (103); patterning the graphene layer (105) to define at least one channel region; applying a lithographic process to define at least two contact areas in the graphene layer; depositing one metallic contact (106) on each one of the at least two defined contact areas of the graphene layer (105); depositing a second layer of an insulating material (107) on the stacked structure, the second layer of an insulating material (107) being made of a second oxide dielectric material different of the first oxide dielectric material of which the first layer of an insulating material (103) is made; and wherein the selectivity to at least one etchant of the first oxide dielectric material is different from the selectivity to said at least one etchant of the second oxide dielectric material.