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NICK OSWALDELECTRICAL AND COMPUTER ENGINEERING
AT OKLAHOMA STATE UNIVERSITY
Terahertz Transistors
History
1947 first transistor Created by John Bardeen, Walter
Brattain and William Shockley Point contact transistor Semiconducting material
Germanium By early 1950’s transistors made
itsway into electronics
Replaced vacuum tubes
Picture from: http://www.porticus.org/bell/belllabs_transistor.html
History Continued
Integrated Circuit 1958 Jack Kilby Combined electrical devices on a single chip
Planar Technology 1958 Jean Horni Created a transistor with a flat profile
IC with Planar Technology 1959 Robert Noyce Combined IC and Planar technology
Moore’s Law
Published in 1965 by Gordon Moore Has been
extremely accurate to this point
Inspired the progression of technology
Has been used to predict the feature size and speed of transistors
Picture from http://en.wikipedia.org/wiki/Moore%27s_Law#_note-0
Proposed THz Transistors
Traditional Transistor But smaller features December 2006 Milton Feng University of Illinois at Urbana-Champagne
Ballistic Transistor August 2006 Quentin Diduck University of Rochester
Carbon Nanotube Field Effect Transistor (CNTFET) Many Different Designs June 2007 Yury A. Tarankanov and Jari M. Kinaret
Traditional Transistor with Smaller Feature size
Switching Speeds 845 GHz when chilled to -55°
C 765 GHz when at room
temperature
Fastest Transistor when proposed
Base Mesa Old Design 1.5μm New Design 550 nm Measured using an SEM
imagePicture from http://www.news.uiuc.edu/NEWS/06/1211transistor.html
Ballistic Transistor
Operation 0 or 1 based on the direction of
flow Direction changes based on the
field applied to the transistor Deflects electrons off a triangle Electrons flow in a plane
Characteristics Materials
indium gallium arsenide indium phosphide Gallium arsenide
70nm feature size Use etching to create the triangle
Picture from http://www.technologyreview.com/Infotech/17368/?a=f
CNTFET
Many different designs Carbon nanotube ring
Semiconducting characteristics Conducting characteristics
Carbon nanotube cantilever Single walled nanotube structure (SWNT)
Lying on a layer of Silicon dioxide Attached to the drain and source
2 separate designs using a metallic multi-walled nanotube structure (MWNT) acting as gate Doubly clamped Singly clamped
CNTFET continued
SWNT Length 1000nm Diameter 1.7nm
MWNT Doubly Clamped
Length 2000nm Support height 30nm
Singly Clamped Length 1000nm Support height 40nm and
60nm Gate bar height 25nm and
40nm Picture used from Yury A. Tarakanov, Jari M. Kinaret, “A Carbon Nanotube Field Effect Transistor with a Suspended Nanotube Gate,” Nano Letters, Vol. 7, No. 8, pp. 2291-2294, June 2007
Conclusions
Moore’s Law is continuing to be an influenceMany new ideas for a THz transistorEventually a complete redesign of the
transistor will be necessary