E-Beam Evaporation: Basic Function

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來自 Duke University 的課程

Nanotechnology: A Maker’s Course

388 個評分

Duke University

Nanotechnology: A Maker’s Course

388 個評分

How can we create nano-structures that are 10,000 times smaller than the diameter of a human hair? How can we “see” at the nano-scale? Through instruction and lab demonstrations, in this course you will obtain a rich understanding of the capabilities of nanotechnology tools, and how to use this equipment for nano-scale fabrication and characterization. The nanoscale is the next frontier of the Maker culture, where designs become reality. To become a Nanotechnology Maker pioneer, we will introduce you to the practical knowledge, skills, and tools that can turn your nanotechnology ideas into physical form and that enable you to image objects at the nano-scale. This course has been developed by faculty and staff experts in nano-fabrication, electron beam microscopy, and nano-characterization through the Research Triangle Nanotechnology Network (RTNN). The RTNN offers training and use of the tools demonstrated in this course to schools and industry through the United States National Nanotechnology Coordinated Infrastructure program. The tools demonstrated in this course are available to the public through the RTNN.

從本節課中

Nanofabrication: Vacuum Pumps and Thin Film Vacuum Deposition

In this module, we will discover how and why a vacuum environment is required in nanofabrication, compare the operation of three types of vacuum pumps, and look at vacuum deposition of thin films using three different methods: sputter evaporation, e-beam evaporation and thermal evaporation.

Thermal Evaporation: Basic Function6:39

Thermal Evaporation: Sample Deposition Demonstration6:46

E-Beam Evaporation: Basic Function4:59

E-Beam Evaporation: Sample Deposition Demonstration5:13

Sputter: Basic Function4:02

Sputter: Sample Deposition Demonstration9:14

與講師見面

Nan M. Jokerst
J. A. Jones Professor of Electrical and Computer Engineering
Electrical and Computer Engineering, Duke University
Carrie Donley
Director of CHANL (Chapel Hill Analytical and Nanofabrication Laboratory)
Applied Physical Sciences, UNC Chapel Hill
James Cahoon
Assistant Professor
Chemistry, UNC Chapel Hill
Jacob Jones
Professor
Materials Science and Engineering, North Carolina State University

[MUSIC]

Hello, I'm Nan Jokerst, and

this is our in-depth video about electron beam vacuum deposition of thin films.

We use vacuum systems to deposit thin layers of materials,

such as metals and insulators, onto our substrates.

The thicknesses of these vacuum deposited layers are very thin,

on the order of 5 nanometers to 250 nanometers.

The three most common thin film deposition techniques are thermal evaporation,

electron beam evaporation, and sputtering.

In this video, I will introduce you to the process of

electron beam evaporation also called e-beam evaporation.

This technique is similar to thermal evaporation but

the material is heated up a little bit differently.

In thermal evaporation, electrical current is used to heat a boat so

that the source material in the boat melts and evaporates.

In electron beam evaporation, a stream of electrons or

an electron beam is aimed at a high purity source material that we want to evaporate.

This beam of electrons heats the material to its melting point and

then evaporates the source material.

This electron beam is well confined.

And one of the advantages of e-beam evaporation is that we can

rotate different source materials into the path of that electron beam.

So that we can deposit multiple material sequentially without

opening the vacuum system which is also called a breaking vacuum or venting.

An e-beam evaporator has two main components.

First is the electron source or electron gun which produces the beam of electrons.

Second, the crucible is where the source material

that we want to evaporate is contained.

This is like the boat for thermal evaporation.

Here is a crucible with gold in it for the source material.

Contained within that electron gun is a filament, the source of the electrons.

And magnets for focusing that electron beam and

directing it towards the crucible.

The electron beam is generated by heating the metal filament to the point that it

glows bright, about 2,500 degrees centigrade.

At this temperature, electrons are so

energetic that some of them leave the surface of the filament.

These electrons are then accelerated toward the source material

using a high voltage electrode.

And a set of magnets steer and

focus the beam onto the source material to be evaporated.

The power level can be to control by adjusting the filament current.

This is very important, since some materials require lower power to melt and

can burn at higher power, while others require higher power just to melt.

The source material is contained in a small crucible.

Depending upon the material being evaporated, the crucible may be made of

tungsten, copper, or even a ceramic for very high temperature deposition.

Because that electron beam is well confined in space,

only a small area of the source material is heated.

This means that there's room for

multiple small source materials in the vacuum chamber.

Systems that hold four materials are very common and

they are called four pocket hearths.

There are four crucibles that fit into the hearth, and

each crucible can hold a different source material.

So that you can have up to four layers of

different materials deposited without breaking vacuum.

The hearth is a rotated holder of copper which is water-cooled.

The water cooling prevents the crucible material from melting and

mixing with the source material or with the hearth itself.

In this configuration, several different materials can be deposited or

sequential back and forth can also be deposited of multi-layer materials.

Electron beam evaporation is one thin film deposition option.

Be sure to take a look at the thermal evaporation and sputter deposition videos

to learn about two other commonly used thin film vacuum deposition techniques.

I hope you enjoyed this lesson.

Thank you for joining me today.

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