Tutorial 1

Derek Wright

Wednesday, January 5th, 2005

This Course

• The Good:– This course could be called: The “How

Everything That’s Cool Works” Course– Mostly qualitative

• If you get how everything works, you’ll do great• If you like to memorize how to do a certain type of

problem, you might not do as well

– Hopefully some good demos– Great way to decide if grad school is right for

you

This Course

• The Bad:– Relies on some stuff you haven’t been taught

yet (process technology)– Have to get used to the idea that things don’t

work the same at the nanometer scale– Textbook is good, but way too expensive

Textbook

• Not recommended• $156• Technology is

changing so fast, most of this book will be obsolete in a few years

• However, it’s a really cool book!

What is Nanotechnology?

• Any technology that has at least one dimension at the nanometer scale– Quantum Wells– Giant Magnetoresistance– Carbon Nanotubes– Things that use tunneling– Atomic Force Microscopes

Why Use Nanotechnology?

• There are two main reasons:– The small feature size allows miniaturization

and high information/work density– The small feature size allows the exploitation

of quantum effects

Examples of Information Density

• Hard Drives now exploit Giant Magnetoresistance (GMR) to greatly increase density

Examples of Information Density

• Display quality is increasing due to feature size reduction

• Organic Light Emitting Diodes are a promising candidate for new displays

Examples of Information Density

• Shrinking feature size means smaller, faster chips

Examples of Quantum Devices

• Quantum computers exploit quantum spin states of molecules to enable bit-level parallelism

Examples of Quantum Devices

• Quantum Wells can selectively trap electrons with quantized energy levels

Examples of Quantum Devices

• Tunnel Diodes make use of an electron being a probability wave (Heisenberg’s Uncertainty Principle) and a highly skewed band diagram.

• Negative Resistance

Examples of Quantum Devices

• “How many electrons does it take to remember the entire contents of the Library of Congress? Only one, according to University of Michigan professor Philip Bucksbaum. Since electrons, like all elementary particles, are actually waves, Bucksbaum has found a way to phase-encode any number of ones and zeros along a single electron's continuously oscillating waveform.” – EE Times

PhotoresistApplication

Exposure/Developing

Deposition/Growth or

Etching

PhotoresistEtching

Building Devices

Deposition vs. Growth

• Deposition:– New material is stuck on top of the substrate

(e.g. Amorphous Silicon)

• Growth:– A form of deposition where new material

reacts with the substrate to form a compound (O2 reacts with Si substrate to form SiO2 insulator)

Wafer

Deposited Material

Wafer

Deposition vs. Growth

Grown Material

Inert material Reactive material

Some Deposition Techniques

• Sputter

• Molecular Beam Epitaxy

• Chemical Vapour Deposition– Thermal CVD– Plasma Enhanced CVD– Low Pressure CVD

• Spin-on

• Printing

Some Growth Techniques

• Uses CVD to cause reactive species to hit the surface

• PECVD is great because it strips electrons off gas-phase molecules and causes many reactive ions to form

Etching Techniques

• Wet Chemical Etching

• Ion Beam Etching

• Reactive Ion Etching

• Focused Ion Beam Etching

Example of RIE in DRAMs

• RIE allows very high aspect ratio trenches to be created

• Extremely useful for shrinking capacitor size in DRAMs

Course Outline

• Process Technology:– Deposition– Growth– Lithogrpahy– Etching– Micromachining– Ashing– Chemo-Mechanical Polishing

Course Outline

• Scanning Probe Techniques:– Scanning Tunnelling Microscopy– Scanning Force Microscopy– Imaging of Soft Materials– Manipulating Atoms and Molecules– Chemical Reactions with STM

Course Outline

• Sensor Arrays and Imaging Systems:– Physical Principles of Sensors– Optical Imaging Systems– IR Imaging Systems– Electronic Nose– Tactile Sensors and Arrays

Course Outline

• Displays:– Liquid Crystal Displays– Organic Light Emitting Diode Displays– Field Emission and Plasma Displays– Electronic Paper

Course Outline

• Logic Devices:– Silicon MOSFETs– Ferroelectric Field Effect Transistors– Resonant Tunneling Quantum Devices– Single-Electron Devices– Carbon Nanotubes

Course Outline

• Mass Storage Devices:– Storage Principles– Hard Disk Drives– Magneto-Optical Discs– Compact and Digital Versatile Discs– AFM-Based Mass Storage

Course Outline

• Nano-BioSystems:– Neuro-Electronic Interfacing– Biomaterials– DNA Microarrays

Useful Websites

• Google (duh)

• ieeexplore.ieee.org

• www.eetimes.com

Thank You!

• This presentation will be available on the web.