Future of Computation with Electronic Nanotechnogy

Presented By

Shubhra Karmakar

CS-603 Nanotechnology 2Spring 2004

Outline

Technology shifts in computation What is electronic nanotechnology? Approaches to nanoelectronic devices Nanoelectronic devices in future computers Solid-state nanoelectronic devices Molecular electronic devices Conclusions

CS-603 Nanotechnology 3Spring 2004

Technology Shifts in Computation

Rapid increase in transistor density i.e., number of transistors/chip

This Increase being dictated primarily by- Need for greater computational speed

- Need for greater computational memory

Increase in transistor density Scaling down device sizes

- Size shift: Inches to Microns to Nanometers

- Technology shift: Micron technology to

Nanotechnology

CS-603 Nanotechnology 4Spring 2004

What is Electronic Nanotechnology ? Electronic Nanotechnology Nanoelectronics

Nanoelectronics: Development of electronic devices having smallest feature size between 1 to 10 nm

Possible electronic devices in computers that can be scaled down to nano levels- CMOS- Memory- Switches

CS-603 Nanotechnology 5Spring 2004

Place of Nanoelectronics in Moore’s Space

1.E+11

CMOSDoubles every 1.0 year

TransistorsDoubled every 2.3 year

1.E+10

1.E+09

1.E+06

1.E+03

1.E+00

1.E-03

1.E-06

Mechanical RelaysDoubled every 7.5 years

Nanometer

doubles every few months?

1880 1920 1960 2000 20302010 2020198019401900

From Gray Turing Award Lecture

Ops

/se

c

CS-603 Nanotechnology 6Spring 2004

Approaches To Nanoelectronic Devices Two approaches:

- Develop “nano” descendants of present solid-state

microelectronics

- Fabricate nano devices from molecules Molecular

electronics approachPath I

Scaling down current S-State devicesPath II

Molecular Electronics

CS-603 Nanotechnology 7Spring 2004

Promising Nanoelectronic Devices in Future Computers

Path I: Nanoelectronic Solid-State Devices- Nano CMOS

- Resonant Tunneling Diode (RTD)

- Single Electron Transistor (SET)

Path II: Molecular Electronic Devices- Molecular Electronic RTD

- Spintronics

Quantum-Effect Devices

CS-603 Nanotechnology 8Spring 2004

The Future of CMOS

Current VLSI systems rely heavily on CMOS technology With nano miniaturization:

- A CMOS is predicted to have 1010 transistors by 2012

- Operating speeds will be 10 – 15 GHz (compare to current 1 GHz !) Example: Today’s CMOS gate length = 120 nm 22 nm (2014)

100 nm

CS-603 Nanotechnology 9Spring 2004

Scaling Limits of CMOS As we scale down, devices

will become- More variable

- More faulty

As we scale down, fabrication will become

- More expensive

- More constrained

As we scale down, design will become

- More complicated

- More expensive

From Shibayama et al, 1997

CS-603 Nanotechnology 10Spring 2004

Resonant Tunneling Diode (RTD)

Made by placing insulating barriers on a semiconductor => creates island or potential well between them

Only finite number of discrete energy levels are permitted in the island

Electrons can pass through the island by quantum tunneling- If incoming electron energy matches (or

resonates) with an energy state inside the island, then current flows through: “ON” state

- If energy states inside and outside do not match: “OFF” state

Multiple logic states are possible- As voltage bias is increased and resonant states are established, switches “ON. Then switches “OFF” and then switches “ON” as soon as next level energy states match

CS-603 Nanotechnology 11Spring 2004

Single Electron Transistor (SET)

Bell Lab researchers fabricated the first SET in 1987 Similar tunneling concept as RTDs

- One electron tunnels from source to drain, through the barriers

CS-603 Nanotechnology 12Spring 2004

Summary of Quantum-State Nanoelectronic Devices

Device Advantages Disadvantages Status

RTD - Multiple logic states- Semiconductor

based- Capable of large

scale fabrication

- Same scaling

limitations as

CMOS

- In production

SET - High Gain- Similar operation to

FET

- Very low

temperature- Control

challenges

- Experimental

CS-603 Nanotechnology 13Spring 2004

Molecular Electronic Devices for Future Computers

Molecular Electronics – Uses covalently bonded molecules to act as wires and switching devices

- Molecules are natural nanometer-scale structuresE.g., A molecular switching device is only 1.5 nm wide!

Molecular electronics will bring the ultimate revolution in computing power

- 1 trillion switching devices on a single CPU chip!- Terabyte level memory capacities!

Primary advantage – can be synthesized in large numbers; in the order of Avagadro’s number (1023)

Present day challenge is to develop methods to incorporate these devices in circuits

CS-603 Nanotechnology 14Spring 2004

Molecular Electronic Devices(…continued)

Molecular Electronic Resonant Tunneling Diode- Concept is similar to solid-state RTD

Chains of Benzene ring act like conductive wires- “CH2” (Methylene group) act as electron barriers

- Island or potential well formed between them Potential well in molecular RTDs is 10 to 100 times less than

solid-state RTDs

CS-603 Nanotechnology 15Spring 2004

Molecular Electronic Devices(…continued)

Spintronics- Spintronics Spin electronics Magneto-electronics- Discovered in 1988 by German and French physicists; IBM commercialized the concept in 1997- Exploits the “spin” of electrons, rather than “charge” in information circuits- Information is stored into spins as a particular spin orientation (up or down)- Spins, being attached to mobile electrons, carry the information along a wire

Spin orientation of electrons survive for a relatively longer time, which makes Spintronic devices attractive for memory storage devices in computers

CS-603 Nanotechnology 16Spring 2004

Spintronics(…continued)

Computers

Hard Drive- Uses magnetic spin to store long- term information- Information is retained on power loss

RAM & CPU- Uses charge to store information- Information is lost on power loss

Magnetic disk drives--like this 1 GB IBM Microdrive, are the most common devices that takes advantage of Spintronics

CS-603 Nanotechnology 17Spring 2004

Spintronics(…continued)

Advantages of Spintronics-based computers

- Non-volatile: no loss of data during a power loss

- Compact: because of increased miniaturization

- Energy efficient

- Highly customizable: Reprogrammable CPU

Magnetic RAM is a more imminent development than a magnetic CPU (CPU involves more complex h/w)

CS-603 Nanotechnology 18Spring 2004

Spintronics(…continued)

Potential Market for Nanoelectronic Memory and Logic Products, 2003-2013

Adapted from: BCC Research Report

CS-603 Nanotechnology 19Spring 2004

Snapshot of Active Research in Nano Devices

Nano CMOS

RTDs SETs Molecular Devices

MRAM Hard Drive

CS-603 Nanotechnology 20Spring 2004

Conclusions

The strides being made in nanoelectronics promise an exciting future for computation

Despite enormous progress in demonstration of nanoelectronic devices, many challenges remain

- Solid-state nanoelectronic devices: Important challenges are that

of fabrication, reliability and design

- Molecular electronic devices: Challenge is to incorporate these

devices in circuits Spintronics device development and commercialization of this

technology in memory devices of computers seems to hold tremendous potential

"Don't worry about what anybody else is going to do… The best way to predict the future is to invent it. Really smart people with reasonable funding can do just about anything that doesn't violate too many of Newton's Laws!" — Alan Kay in 1971

CS-603 Nanotechnology 21Spring 2004

References

http://www.cellmatrix.com/entryway/products/pub/Beckett2002.pdf http://nanotech-now.com/spintronics.htm http://policy.iop.org/v_production/v5.html http://www.mitre.org/tech/nanotech/ http://www-2.cs.cmu.edu/~phoenix/ http://www.anl.gov/OPA/factsheets01/H-04.pdf http://www.bccresearch.com/editors/RGB-286.html http://physicsweb.org/article/world/11/9/7/1

CS-603 Nanotechnology 22Spring 2004

Questions?