Double Contact Geometry for Carbon Nanotube Thin Film Devices
Solution Overview
Problem
The alignment issues of carbon nanotubes in thin-film transistors lead to high contact resistance due to the bends and curves of the nanotubes, making it difficult to establish effective electrical coupling with contacts.
Innovation Solution
A double-contact geometry is introduced, where a second contact layer is formed to electrically couple with carbon nanotubes that are not directly aligned with the first contact layer, increasing the number of nanotubes in direct contact and reducing contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single contact layer is used to electrically couple carbon nanotubes, then the device structure remains simple, but high contact resistance occurs due to misalignment of nanotube ends
Solution Approach 1:
The contact structure is segmented into two distinct contact layers: a first contact layer positioned at the bottom and a second contact layer positioned at the top. This segmentation allows independent optimization of each layer's function - the first contact layer provides structural support and initial electrical connection, while the second contact layer ensures reliable electrical coupling with the carbon nanotube ends, thereby resolving the contradiction between connection reliability and structural simplicity.
Solution Approach 2:
The contact structure transitions from a single-plane (2D) contact to a multi-layer (3D) contact architecture. By stacking contact layers vertically, the invention creates additional electrical connection pathways through the third dimension, enabling reliable electrical coupling even when nanotube ends are misaligned or curved, thus improving reliability without significantly increasing horizontal complexity.
2Adaptability or versatility
If carbon nanotubes are assembled with bends and curves, then flexibility and coverage are improved, but alignment of nanotube ends deteriorates leading to high contact resistance
Solution Approach 1:
By introducing a vertical stacking dimension with multiple contact layers, the invention compensates for horizontal misalignment of nanotube ends. The multi-layer structure creates overlapping contact zones that can accommodate nanotubes with various bends and curves, allowing the system to maintain good electrical contact despite variations in nanotube orientation and position.
Solution Approach 2:
The contact structure implements local quality optimization by positioning the second contact layer specifically where nanotube ends are most likely to make contact. This localized enhancement of contact capability at critical interfaces ensures reliable electrical coupling precisely where needed, while maintaining flexibility in the overall nanotube assembly configuration.
Data Source
AI summary
A method of fabricating a semiconductor device is disclosed. A first contact layer of the semiconductor device is fabricated. An electrical connection is formed between a carbon nanotube and the first contact layer by electrically coupling of the carbon nanotube and a second contact layer. The first contact layer and second contact layer may be electrically coupled.