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
TelephoneHistory3/History3.html

3. Importance Transistors replaced vacuum tubes.
“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
19 68
19 58
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
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19 34
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How a transistor works?
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5. 1874 Ferdinand Braun discovered Rectification ◄
crystals that can conduct current in only one direction under certain conditions. ◄

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. ◄

7. 1895
Guglielmo Marconi - sent a radio signal over a distance of more than a mile.
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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)
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.
Diode_vacuum_tube.png ◄

9. 1898 Thomson discovered the electron. ◄ ◄

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.
*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.
vacuum_tube.png ◄

11. 1907 Bell telephone patents expire.
AT&T (Bell’s company) bought De Forest’s triode patent.
Result: transcontinental telephone service. ◄

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
lilienfeld.htm ◄

13. 1934
German Physicist Dr. Oskar Heil patented the field effect transistor ◄

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 ◄

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.
transistor/history.html ◄

16. 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.
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transistor/history.html
ransistor/history.html
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17. 1947 cont.

18. 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
Picture%20First%20junction%20transistor.jpg

19. 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. ◄

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 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. ◄

22. 1955
Foundation of Shockley Semiconductor, sowing the seeds of silicon valley ◄

23. 1957
The traitorous eight abandoned Shockley founding Fairchild Semiconductor. ◄

24. Texas Instruments' first IC
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.
samples/education/images.htm

26. 1968
Bob Noyce and Gordon Moore, two of the traitorous eight together with Andy Grove, form Intel Corporation
background/history/
2006/Intel_logo_nove1_velky.jpg ◄

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. ◄

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. ◄

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
astr511/im/Si-B-doping-JFA.jpg ◄
p-type doping

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

34. Conduction Band: Is a part in which electrons can move freely and can accelerate under an electric field, constituting an electric current.
Energy gap
Conduction Band
Valence Band
Metals
Semiconductors
Insulators
Bigger Energy gap
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. ◄

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
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"Photo: National Research Council of Canada.“
fundamental/nrc-nint_moleculartransistor_e.html ◄

40. Pictorial History of Transistors◄

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
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
You can find two very cool games on transistors in the next link:
tro.html ◄