Carbon Nanotube Transistor Embedded Electrode Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for fabricating carbon nanotube transistors lack scalability and result in performance degradation due to structural and chemical damage, and there is limited control over carbon nanotube alignment and integration with semiconductor manufacturing processes.
Innovation Solution
A method involving self-alignment of carbon nanotubes using an alternating current electrical field between embedded electrodes within a substrate, with a buried gate electrode and embedded electrodes, allowing for parallel alignment and minimization of parasitic capacitance through contact via structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon nanotubes are grown or dispersed globally on a substrate, then easy formation of carbon nanotubes is achieved, but alignment control and integration with semiconductor manufacturing processes become difficult
Solution Approach 1:
The substrate is divided into multiple regions with different electrode configurations. Embedded electrodes are placed in specific patterns (e.g., interdigitated, parallel) to create localized electric fields that guide carbon nanotube alignment only in desired areas, while other regions maintain easy formation characteristics.
Solution Approach 2:
Different regions of the substrate are given different properties: some areas have embedded electrodes for controlled alignment, while other areas maintain simple dispersion for easy formation. The electric field strength, frequency, and electrode geometry are locally optimized to achieve specific alignment degrees in different device regions.
2Manufacturing precision
If carbon nanotubes are placed locally by chemical or electrical means, then alignment control is improved, but structural and chemical damage occurs resulting in performance deterioration
Solution Approach 1:
The patent replaces mechanical manipulation methods (chemical treatment, physical transfer, heating, bending) with an electric field-based alignment mechanism. Carbon nanotubes are aligned using dielectrophoresis or electrophoresis in a solution, allowing gentle positioning without mechanical stress that would cause structural damage.
Solution Approach 2:
The alignment process uses controlled electric field parameters (frequency, amplitude, waveform) to achieve alignment at conditions that do not damage carbon nanotubes. By optimizing these parameters, alignment is achieved while maintaining the structural integrity and electrical properties of the nanotubes.
3Adaptability or versatility
If conventional fabrication processes are used, then existing manufacturing compatibility is maintained, but scalability to smaller dimensions and prevention of structural damage is limited
Solution Approach 1:
Carbon nanotubes are pre-aligned in solution using electric fields before being transferred to the final device structure. This preliminary alignment step ensures correct orientation is achieved before subsequent fabrication steps, enabling scalable production without requiring complex in-situ alignment during later processing stages.
Solution Approach 2:
A solution medium serves as an intermediary carrier for carbon nanotubes during the alignment process. The nanotubes are suspended, aligned, and manipulated in liquid solution using electric fields, then transferred to the solid-state device structure. This intermediary approach enables gentle handling and precise alignment while maintaining compatibility with standard fabrication processes.
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 enables the formation of high-performance carbon nanotube transistors with enhanced drive current and speed, maintaining structural integrity and scalability, while being compatible with semiconductor manufacturing processes.
Implementation Method 1
An alternating current (AC) voltage is applied across the embedded electrodes through a pair of conductive structures that contact the embedded electrodes. An AC electrical field induces carbon nanotubes in the carbon-nanotube-including solution to self-align in the direction of the AC electrical field between the two embedded electrodes.
Implementation Method 2
applying a voltage between the two embedded electrodes. An alternating current (AC) voltage is applied across the embedded electrodes through a pair of conductive structures that contact the embedded electrodes. An AC electrical field induces carbon nanotubes in the carbon-nanotube-including solution to self-align in the direction of the AC electrical field
Data Source
AI summary
Carbon nanotubes can be aligned with compatibility with semiconductor manufacturing processes, with scalability for forming smaller devices, and without performance degradation related to structural damages. A planar structure including a buried gate electrode and two embedded electrodes are formed. After forming a gate dielectric, carbon nanotubes are assembled in a solution on a surface of the gate dielectric along the direction of an alternating current (AC) electrical field generated by applying a voltage between the two embedded electrodes. A source contact electrode and a drain contact electrode are formed by depositing a conductive material on both ends of the carbon nanotubes. Each of the source and drain contact electrodes can be electrically shorted to an underlying embedded electrode to reduce parasitic capacitance.