1. NICK OSWALD ELECTRICAL AND COMPUTER ENGINEERING AT OKLAHOMA STATE UNIVERSITY Terahertz Transistors

2. 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 its way into electronics  Replaced vacuum tubes Picture from: http://www.porticus.org/bell/belllabs_transistor.htmlhttp://www.porticus.org/bell/belllabs_transistor.html

3. 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

4. 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-0http://en.wikipedia.org/wiki/Moore%27s_Law#_note-0

5. 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

6. 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 image Picture from http://www.news.uiuc.edu/NEWS/06/1211transistor.htmlhttp://www.news.uiuc.edu/NEWS/06/1211transistor.html

7. 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=fhttp://www.technologyreview.com/Infotech/17368/?a=f

8. 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

9. 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

10. Conclusions Moore’s Law is continuing to be an influence Many new ideas for a THz transistor Eventually a complete redesign of the transistor will be necessary