Single-electron Devices Speaker: Qiaoyan Yu [email protected] ECE423 12-16-2006.

Single-electron Single-electron DevicesDevices

Speaker: Qiaoyan [email protected]

ECE42312-16-2006

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Agenda Milestone Motivations New characteristics Single-electron transistor (SET) Challenges Conclusions

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Milestone In 1909, Millikan first illustrated the

manipulation of single electrons. In 1985, Dmitri Averin & Konstantin

Likharev proposed single-electron transistor.

In 1987, Theodore Fulton & Gerald Doald at Bell lab fabricated and demonstrated SET.

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Motivation Power consumption challenges high

performance and high density chip design Faster and more information processing

resulting in generating more heat flux Reduce the corresponding charge per bit! Single-electron Device!!!

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SED new characteristics Exploit the quantum effect of tunneling

Control and measure the movement of single electron

Charge doest not flow continuously Instead in a quantized way

Extremely high charge sensitivity High precise for charge measurement

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Single-electron transistor (SET) Architecture Equivalent circuit Operation principle I-V curve SET VS. MOSFET

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Architecture

gateCg

Vg

Vb

Source Drain

Tunnel junctions

island

C1 C2

+q1 -q1 +q2 -q2

q

V2V1

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Equivalent circuit

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Operation principle

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Operation principle

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Operation principle

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I-V curve

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SET vs. MOSFET Structure

Two tunneling barrier vs. inversion channel Size

Extremely small vs. large (although scaled down) Main physical principle

Coulomb blockade vs. electron diffusion Threshold voltage & source-drain current

Periodic vs. not periodic Sensitivity

High vs. low (10000X) Power

Low vs. high

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SED challenges Difficult to precisely control the device

implementation Characteristic of the device varies

significantly from location to location Suffer from “offset charges”

Randomly fluctuation of control signal

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Conclusions Because of natural small dimension, SED is a

potential solution for continue silicon scaling. It is not clear that SET replaces FET. It is certain that quantum properties of electrons

will be crucial in the design of electron devices. Electron beam lithography and scanning probe

techniques offer the best prospects for the future. Some more esoteric techniques based on atomic

particle deposition and colloid chemistry may also provide some benefits.

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The End

Thank You!Any questions?