Transcript Parametron-Inspired NEMS Oscillator Logic Elements

Microelectromechanical
Oscillator-Based Digital Logic
Anthony Yeh
EE C235, Spring 2009
Introduction
• Today’s Digital Computing
▫ Transistor-based (switches that are on or off)
• The Parametron (1950s)
▫ Dr. Eiichi Goto (University of Tokyo)
▫ Digital computing element (analogous to transistor)
▫ Based on interference of
parametric oscillators
(instead of switches)
▫ Simpler, cheaper, more
reliable than transistors of the
time
“The History of Computing Project,” http://www.thocp.net/hardware/parametron.htm
Parametric Oscillation
• Parametric oscillator versus driven oscillator
• Parametron used parametric oscillation of LC
resonators (by periodically varying capacitance)
Eiichi Goto, "The Parametron, a Digital Computing Element which Utilizes Parametric Oscillation,” Proceedings of the IRE, 1959
Parametron Binary Logic
• Parametric oscillation has two
stable states of oscillation
 Separated by 180 degree phase
shift
 Very stable
 No drift (only two allowed stable
states, energy concentrated in
resonant frequency)
 Strong force (voltage) required to
switch between bistable states
(unless oscillation is quenched
and then restarted)
 Selection of state determined by
initial small oscillation
 Outputs from multiple
Parametrons can be combined to
form the input to another
Parametron to create logic gates
Eiichi Goto, "The Parametron, a Digital Computing Element which Utilizes Parametric Oscillation,” Proceedings of the IRE, 1959
Microelectromechanical Parametron
• I. Mahboob, H. Yamaguchi
▫ NTT Basic Research
Laboratories, Japan
▫ Demonstrated binary bit storage
and bit flip
• GaAs beam (260 x 84 x 1.35 um)
▫ Oscillates in out-of-plane
direction
• Parametric oscillation
▫ Vary spring constant of GaAs
beam through piezoelectric effect
▫ Quantum wells at beam ends
concentrate electric fields to
achieve efficient actuation
I. Mahboob, H. Yamaguchi, “Bit storage and bit flip operations in an electromechanical oscillator,” Nature Nanotechnology, May 2008
Bit Storage and Bit Flip
• Parametric actuation (piezoelectric)
• Trigger switch (small initial oscillation)
I. Mahboob, H. Yamaguchi, “Bit storage and bit flip operations in an electromechanical oscillator,” Nature Nanotechnology, May 2008
Technological Potential
• Detailed architecture for Parametron logic already
exists
▫ As opposed to other recent mechanical logic devices
• Electromechanical oscillators can be scaled to
NEMS
▫
▫
▫
▫
▫
Projection: 1um x 100nm oscillator beam
Operation frequencies up to 1GHz
108 bits/cm2 density
Power for bit flip: 10pW (comparable to CMOS)
Power for stable oscillation: ~0.01pW
• Nanoelectromechanical logic-based computers
I. Mahboob, H. Yamaguchi, “Bit storage and bit flip operations in an electromechanical oscillator,” Nature Nanotechnology, May 2008