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Design of Small Chemical Vapor Deposition System

for Materials Research Application

Shamil Baldeosingh Dasney Joseph

Walter McKinley

March 4th , 2010

EML 4905 Senior Design ProjectAdvisor: Dr. K. H. WuMarch 24, 2010

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Overview

Background Problem Statement Design Specifications Conceptual Designs Project Management Future Plans

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Chemical Vapor Deposition for Carbon Nanotube (CNT) Synthesis

Chemical Vapor Deposition ( CVD )

Widely used for engineering applications

• Scalable to industrial production• 20-100 % yield

• Controllable parameters to determine properties

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What Are Carbon Nanotubes?

Large Research Interest

Properties• Mechanical• Electrical • Thermal• Novel Applications

Variations• Dimensions and Geometry• Quality and Yield

Zhao et al., Physical Review Letters,

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Problem Statement

CNT synthesis for current CVD system 3 hours for sample size of 1 – 5 grams

▪ Furnace heating of entire reaction chamber▪ Such a large sample size is not necessary for

research

CNT synthesis for proposed CVD system 0.5 hours for sample size of less than 1

gram▪ Localized heating of gases and substrate▪ Appropriate for research applications

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System Constraints

Preheated Gas Temperature• At least 400 Ac

Substrate Temperature• 600-1000 Ac

   Volumetric flow Rate (mL/min)

PROCESS GAS Hydrogen (H2) 400PRECURSOR

GAS Acetylene (C2H2) 100

CARRIER GAS Argon (Ar) 600

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Design Specifications

Packaging Accessibility

Substrate should be easily loaded Maintenance of system

Gas flow Reynolds number << 2100 : Laminar

Flow Peclet number << 1 Knudsen number > 1

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Conceptual Design AUniform Diameter Tube

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Conceptual Design B Variable Diameter Tube

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Conceptual Design C Modular Cube

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Comparison of Conceptual Designs

Design AStraight Tube

Design BVariable Cross Section Tube

Design CCube

Packaging 4 4 1

Accessibility

5 5 1

Gas Flow 3 2 4

Price 1 2 5

Excellent – 1 Very Good -2 Good – 3 Fair – 4Poor - 5

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Heating Considerations

Substrate Material• Wafer • Powder

Resistive Heating Element• Material• Configurations• Life span

Thermal Strength• Thermal Shock• Thermal Expansion• Deflection

Power Input• AC vs. DC• H-Current/ L-Voltage• L-Voltage/H-Current

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Division of Responsibility

Heat Generation Dasney Joseph

Instrumentation and Fluid Mechanics Shamil Baldeosingh

Conceptual Designs and Prototype Walter McKinley

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Gantt Chart -Spring 2010

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Gantt Chart - Fall 2010

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Human Cost

0

5

10

15

20

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January February March April

TIME (hours)

SHAMIL DASNEY WAL-TER

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Future Work

Design Modeling• SolidWorks

Simulation• ANSYS CFX

▪ Fluid Mechanics▪ Heat Transfer from

Resistive Heating Elements

Instrumentation and Control• LabVIEW• Thermocouple• Infrared Temperature

Sensor• Mass Flow Controller

Prototype Testing• Scanning Electron

Microscope ( SEM ) ▪ Verify growth of CNT’s

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Acknowledgments

Dr. Wu ( Florida International University ) Amit Datye ( Oak Ridge National

Laboratory ) John Hart ( Massachusetts Institute of

Technology )

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Questions & Comments