Transistor

1. Transistor Victor Hugo Estrada Rivera University of Texas at El Paso Molecular Electronics Chem 5369

2. Definition • An electronic device made of a semiconductor that can act as an insulator and a conductor. • The ability to change from these two states enables the device switch or amplify. • It has of three components: • Source • Gate • Drain http://www.privateline.com/ TelephoneHistory3/History3.html

3. Importance “The Transistor was probably the most important invention of the 20th Century and the story behind the invention is one  of clashing egos and top secret research.” Ira Flatow • Transistors replaced vacuum tubes. • Transistors are central to the Integrated Circuit, and therefore, all electronic devices of the information age, such as: pc’s, cellular phones, ipods, pda’s, intelligent cars and buildings…….. are made possible.

4. Timeline 1968 1958 • Click on a Year to Learn its Significance • Click on the Blue Triangle to Return • You can also click to see how a transistor works 1957 1955 1950 1948 1947 1945 1936 1934 1928 1907 1906 1898 1895 1883 How a transistor works? 1874

5. 1874 • Ferdinand Braun discovered Rectification • crystals that can conduct current in only one direction under certain conditions. http://en.wikipedia.org/wiki/Image:Ferdinand_Braun.jpg ◄

6. 1883 • Edison effect ( thermionic emission). • The flow of electrons from metals caused by thermal vibration energy (heat) that overcomes the electrostatic forces that hold the electrons to the surface. ◄ http://en.wikipedia.org/wiki/Image:Thomas_Edison.jpg

7. 1895 • Guglielmo Marconi -sent a radio signal over a distance of more than a mile. http://en.wikipedia.org/wiki/Image:Marconi.jpg ◄

8. 1895 • John Ambrose Fleming -developed the Vacuum Tube • a device that modify a signal by controlling the movement of electrons in an evacuated space. • The electrons flow only from filament to plate creating a diode (a device that can conduct current only in one direction) http://concise.britannica.com/ebc/art-58608 http://en.wikipedia.org/wiki/Image: Diode_vacuum_tube.png ◄

9. 1898 • Thomson discovered the electron. http://en.wikipedia.org/wiki/Image:Jj-thomson2.jpg ◄

10. 1906 • Lee De Forest -Triode in vacuum tube (amplify signals) allowing farther telephone conversations. • The problems with this Triode is that it was unreliable and used a lot of power. http://en.wikipedia.org/wiki/Image:Deforest.jpg http://en.wikipedia.org/wiki/Image:Triode_ vacuum_tube.png ◄

11. 1907 • Bell telephone patents expire. • AT&T (Bell’s company) bought De Forest’s triode patent. • Result: transcontinental telephone service. http://en.wikipedia.org/wiki/Image:Alexander_Graham_Bell22.jpg ◄

12. 1928 • The first patents for the transistor principle were registered in Germany by Julius Edgar Lilienfield. • He proposed the basic principle behind the MOS field-effect transistor http://chem.ch.huji.ac.il/~eugeniik/history/ lilienfeld.htm ◄

13. 1934 • German Physicist Dr. Oskar Heil patented the field effect transistor http://www.precide.ch/eng/eheil/eheil.htm ◄

14. 1936 • Mervin Kelly Bell Lab's director of research. He felt that to provide the best phone service it will need a better amplifier; the answer might lie in semiconductors. And he formed a department dedicated to solid state science http://www.pbs.org/transistor/album1/addlbios/kelly.html ◄

15. 1945 • Bill Shockley the team leader of the solid state department (Hell’s Bell Lab) hired Walter Brattain and John Bardeen. • He designed the first semiconductor amplifier, relying on the field effect. • His device was a small cylinder coated thinly with silicon, mounted close to a small, metal plate. • The device didn't work, and Shockley assigned Bardeen and Brattain to find out why. http://www.lucent.com/minds/ transistor/history.html ◄

16. http://www.lucent.com/minds/ transistor/history.html http://www.lucent.com/minds/t ransistor/history.html http://www.lucent.com/minds /transistor/history.html 1947 • Bardeen and Brattain built the point contact transistor. • They made it from strips of gold foil on a plastic triangle, pushed down into contact with slab of germanium. ◄

17. 1947 cont.

18. Shockley make the Junction transistor (sandwich). This transistor was more practical and easier to fabricate. The Junction Transistor became the central device of the electronic age 1947 cont. http://www.ecse.rpi.edu/Homepages/schubert/Unused%20stuff/Educational%20resources/ Picture%20First%20junction%20transistor.jpg

19. A thin piece of semiconductor of one type between two slices of another type, is able to control the flow of the current between emitter and the collector. Even if the input current is weak, the transistor can control a strong current. The effect accomplish is that the current through the collector mimics and amplify the behavior of the current through the Emitter. 1947 cont. ◄

20. 1948 • Bells Lab unveil the transistor. • They decided to name it transistor instead of Point-contact solid state amplifier. • John Pierce invented the name, combining transresistance with the ending common to devices, like varistor and thermistor. ◄

21. 1950’s • Sony receives a license from Bell Labs to build transistors • In 1946 Sony produced products for radio repair. In 1950 they decided to build something for the mass consumption; the transistor radio. • In United States they used the transistors primarily for computers and military uses. http://www.sony.net/Fun/SH/1-6/h2.html ◄

22. Foundation of Shockley Semiconductor, sowing the seeds of silicon valley 1955 http://en.wikipedia.org/wiki/Image:SJPan.jpg ◄ http://en.wikipedia.org/wiki/Image:ShockleyBldg.jpg

23. 1957 • The traitorous eight abandoned Shockley founding Fairchild Semiconductor. http://www.fairchildsemi.com/company/history_1957.html ◄

24. 1958 • Jack Kilby of Texas Instruments – Invent the Integrated Circuit (IC) • It occurred to him that all parts of a circuit could be made out of the same piece of silicon. • The entire circuit could be built out of a single crystal • Reducing the size • Easier to produce Texas Instruments' first IC ◄

25. 1958 cont. - Integrated Circuit • A single device that contains an interconnected array of elements like transistors, resistors, capacitors, and electrical circuits contained in a silicon wafer. http://www.helicon.co.uk/online/datasets/ samples/education/images.htm http://www.ece.uiuc.edu/grad/7reasons/5reputation.html

26. http://www.itnews.sk/buxus_dev/images/ 2006/Intel_logo_nove1_velky.jpg http://www.granneman.com/techinfo/ background/history/ 1968 • Bob Noyce and Gordon Moore, two of the traitorous eight together with Andy Grove, form Intel Corporation ◄

27. How a Transistor Works • The transistor can function as: • An insulator • A conductor • The transistor's ability to fluctuate between these two states that enables to switch or amplify. • The transistor has many applications, but only two basic functions: switching and modulation (amplification). • In the simplest sense, the transistor works like a dimmer. • With a push the knob of the dimmer, the light comes on and off. You have a switch. Rotate the knob back and forth, and the light grows brighter, dimmer, brighter, dimmer. Than you have a modulator. ◄

28. How a Transistor Works cont. • Both the dimmer and the transistor can control current flow. • Both can act as a switch and as a modulator/amplifier. • The important difference is that the “hand” operating the transistor is millions of times faster. http://www.ieicorp.com/consum/dimmer.gif ◄

29. Transistors are made of semi-conductors such as silicon and gallium arsenide. These materials carry electricity not well enough to be called conductors; not badly enough to be called insulators. Hence their name semiconductor. The importance of a transistor is in its ability to control its own semi conductance, namely acting like a conductor when needed, or as an insulator (nonconductor) when that is needed. ◄

30. You can compare a transistor to an ordinary faucet. • The water enters the faucet in the pipeline from the water distributor, which would correspond to the source in the Transistor. • The water then leaves the faucet into the sink, this would be the drain in the Transistor. • The water tap controls the amount, flow, of water. In the Transistor the gate operates as this controller. • With a small force you can control the water flow with the water tap, just as you can control the current flowing from the source to the drain, with a small change of the charge of the gate. ◄ http://nobelprize.org/educational_games/physics/transistor/function/watertap.html

31. Transistors are Made of Silicon • Silicon is a grey colored element with crystalline structure. • It is the second most abundant element in the earth's crust, after oxygen. • Silicon is always found in combined form in nature, often with oxygen as quartz, and is found in rocks and silica sand. • To be able to use silicon as a semiconductor, it needs to be in a very pure form. • If there is more than one impure particle in a million, the silicon can not be used. • Silicon is the most frequently used semiconducting material today. ◄

32. Doping • The addition of a small amount of a different substance to a pure semiconductor crystal. • The impurities give an excess of conducting electrons or an excess of conducting holes which is crucial for making a working transistor. n-type doping http://www.astro.virginia.edu/class/oconnell/ astr511/im/Si-B-doping-JFA.jpg ◄ p-type doping

33. Donor doping Acceptor doping http://131.104.156.23/Lectures/CHEM_462/462_chapter_1.html http://hyperphysics.phy-astr.gsu.edu/ Hbase/solids/dsem.html#c2 ◄

34. Conduction Band Metals Valence Band Conduction Band Semiconductors Energy gap Valence Band Conduction Band Bigger Energy gap Insulators Valence Band Conduction Band: Is a part in which electrons can move freely and can accelerate under an electric field, constituting an electric current. Energy Gap: Is the energy difference between the valence gap and the conduction band Valence Band: Is a part of the molecule, called band, where you can find the electrons ◄

35. Transistor types • MOS - Metal Oxide Semiconductor • FET - Field Effect Transistor • BJT - Bipolar Junction Transistor ◄

36. Moore’s Law • It’s an observation made by Gordon E. Moore, in which he predicted that the number of transistors, inside an Integrated Circuit, could be doubled every 24 months. • At the density that also minimized the cost of a transistor. ◄

37. ◄ http://upload.wikimedia.org/wikipedia/commons/0/06/Moore_Law_diagram_%282004%29.png

38. Transistor problems • Power density increased • Device variability • Reliability • Complexity • Leakage • Power dissipation limits device density • Transistor will operate near ultimate limits of size and quality – eventually, no transistor can be fundamentally better ◄

39. The Future of transistors • Molecular electronics • Carbon nanotubes transistors • Nanowire transistors • Quantum computing • CMOS devices will add functionality to CMOS non-volatile memory, opto-electronics, sensing…. • CMOS technology will address new markets macroelectronics, bio-medical devices, … • Biology may provide inspiration for new technologies bottom-up assembly, human intelligence "Photo: National Research Council of Canada.“ http://www.nrc-cnrc.gc.ca/multimedia/picture/ fundamental/nrc-nint_moleculartransistor_e.html ◄

40. Pictorial History of Transistors ◄ http://www.bellsystemmemorial.com/belllabs_transistor.html

41. Further Resources • Riordan, Michael and Lillian Hoddeson. Crystal Fire: The Invention of the Transistor and the Birth of the Information Age. New York: W. W. Norton and Company, 1997. • Brattain, Walter H. "Genesis of the Transistor." The Physics Teacher. (March, 1968) pp. 109-114. • Hoddeson, Lillian. "The Roots of Solid State Research at Bell Labs." Physics Today. (March, 1997). • Holonyak, Jr., Nick."John Bardeen and the Point-Contact Transistor." Physics Today. • (April, 1992). • Shockley, William. "How We Invented the Transistor." New Scientist 21. (December, 1972) pp. 689-91. • http://www.pbs.org/transistor • http://www.aip.org/history • http://www.lucent.com/minds/transistor/history.html • http://chem.ch.huji.ac.il/~eugeniik/history/lilienfeld.htm • http://en.wikipedia.org/wiki/Main_Page • You can find two very cool games on transistors in the next link: • http://nobelprize.org/educational_games/physics/transistor/function/intro.html ◄