Transistor

TransistorVictor Hugo Estrada RiveraUniversity of Texas at El PasoMolecular Electronics Chem 5369

DefinitionAn 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:SourceGateDrainhttp://www.privateline.com/TelephoneHistory3/History3.html

ImportanceThe Transistor was probably the most important invention of the 20th Centuryand the story behind the invention is oneof 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: pcs, cellular phones, ipods, pdas, intelligent cars and buildings.. are made possible.

Timeline18741895190619451947194819501957195819681883189819071955193419281936How a transistor works?Click on a Year to Learn its SignificanceClick on the Blue Triangle to ReturnYou can also click to see how a transistor works

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

1883Edison 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

1895Guglielmo Marconi -sent a radio signal over a distance of more than a mile.

http://en.wikipedia.org/wiki/Image:Marconi.jpg

1895John Ambrose Fleming -developed the Vacuum Tubea 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://en.wikipedia.org/wiki/Image:Diode_vacuum_tube.pnghttp://concise.britannica.com/ebc/art-58608

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

1906Lee 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.jpghttp://en.wikipedia.org/wiki/Image:Triode_vacuum_tube.png

1907Bell telephone patents expire.AT&T (Bells company) bought De Forests triode patent.Result: transcontinental telephone service.

http://en.wikipedia.org/wiki/Image:Alexander_Graham_Bell22.jpg

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

1934German Physicist Dr. Oskar Heil patented the field effect transistorhttp://www.precide.ch/eng/eheil/eheil.htm

1936Mervin 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

1945Bill Shockley the team leader of the solid state department (Hells 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

1947Bardeen 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.

1947 cont.

1947 cont.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 http://www.ecse.rpi.edu/Homepages/schubert/Unused%20stuff/Educational%20resources/Picture%20First%20junction%20transistor.jpg

1947 cont.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.

1948Bells 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.

1950sSony receives a license from Bell Labs to build transistorsIn 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

1955Foundation of Shockley Semiconductor, sowing the seeds of silicon valleyhttp://en.wikipedia.org/wiki/Image:SJPan.jpghttp://en.wikipedia.org/wiki/Image:ShockleyBldg.jpg

1957The traitorous eight abandoned Shockley founding Fairchild Semiconductor.

http://www.fairchildsemi.com/company/history_1957.html

1958Jack 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

1958 cont. - Integrated CircuitA 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.htmhttp://www.ece.uiuc.edu/grad/7reasons/5reputation.html

1968Bob Noyce and Gordon Moore, two of the traitorous eight together with Andy Grove, form Intel Corporation

How a Transistor WorksThe transistor can function as:An insulator A conductorThe 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.

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

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.

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

Transistors are Made of SiliconSilicon 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.

DopingThe 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.http://www.astro.virginia.edu/class/oconnell/astr511/im/Si-B-doping-JFA.jpgn-type dopingp-type doping

Acceptor dopingDonor dopinghttp://131.104.156.23/Lectures/CHEM_462/462_chapter_1.htmlhttp://hyperphysics.phy-astr.gsu.edu/Hbase/solids/dsem.html#c2

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

Transistor typesMOS - Metal Oxide Semiconductor FET - Field Effect Transistor BJT - Bipolar Junction Transistor

Moores LawIts 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.

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

Transistor problemsPower density increasedDevice variabilityReliabilityComplexityLeakagePower dissipation limits device densityTransistor will operate near ultimate limits of size and quality eventually, no transistor can be fundamentally better

The Future of transistorsMolecular electronicsCarbon nanotubes transistorsNanowire transistorsQuantum computingCMOS 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

Pictorial History of Transistorshttp://www.bellsystemmemorial.com/belllabs_transistor.html

Further ResourcesRiordan, 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/transistorhttp://www.aip.org/historyhttp://www.lucent.com/minds/transistor/history.htmlhttp://chem.ch.huji.ac.il/~eugeniik/history/lilienfeld.htmhttp://en.wikipedia.org/wiki/Main_PageYou can find two very cool games on transistors in the next link:http://nobelprize.org/educational_games/physics/transistor/function/intro.html

http://www.pbs.org/transistor/album1/index.htmlPermission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". The result is a current of electrons flowing from filament to plate. This cannot work in the reverse direction because the plate is not heated and cannot emit electrons. This very simple example described can thus be seen to operate as a diode: a device that conducts current only in one direction. *This image is in the public domain because its copyright has expired in the United States and those countries with a copyright term of life of the author plus 100 years or less.http://en.wikipedia.org/wiki/Transistor#Historyhttp://chem.ch.huji.ac.il/~eugeniik/history/lilienfeld.htm

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