Transistor Transistor by wulinqing

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Victor Hugo Estrada Rivera
     University of Texas at El Paso
         Molecular Electronics
              Chem 5369
     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
“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.

•Click on a Year to Learn its


•Click on the Blue Triangle to Return

•You can also click to see how a

transistor works


                                           How a transistor works?
   Ferdinand Braun discovered
       crystals that can conduct
        current in only one direction
        under certain conditions.



   Edison effect ( thermionic
       The flow of electrons from
        metals caused by thermal
        vibration energy (heat) that
        overcomes the electrostatic
        forces that hold the electrons
        to the surface.


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


   John Ambrose Fleming -
    developed the Vacuum
       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)

                                         Diode_vacuum_tube.png                     ◄

   Thomson discovered
    the electron.


   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.

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


  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


   German Physicist Dr.
    Oskar Heil patented
    the field effect


   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://

   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
   The device didn't work, and        transistor/history.html

    Shockley assigned Bardeen and
    Brattain to find out why.
   Bardeen and Brattain built the point contact
   They made it from strips of gold foil on a plastic
    triangle, pushed down into contact with slab of

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

   Shockley make the
    Junction transistor
   This transistor was more
    practical and easier to
   The Junction Transistor
    became the central
    device of the electronic
                           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
   The effect accomplish is that the
    current through the collector
    mimics and amplify the behavior
    of the current through the Emitter.

 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.

   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
   In United States they used
    the transistors primarily for

    computers and military uses.
   Foundation of Shockley Semiconductor,
    sowing the seeds of silicon valley

   The traitorous eight abandoned Shockley
    founding Fairchild Semiconductor.


   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
    1958 cont. - Integrated Circuit
   A single device that
    contains an
    interconnected array
    of elements like
    transistors, resistors,
    capacitors, and                                      samples/education/images.htm

    electrical circuits
    contained in a silicon
   Bob Noyce and Gordon Moore, two of the
    traitorous eight together with Andy Grove,
    form Intel Corporation

           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.

    How a Transistor Works cont.
   Both the dimmer and the
    transistor can control
    current flow.
    Both can act as a switch
    and as a
    The important difference
    is that the “hand”
    operating the transistor is
    millions of times faster.

   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.   ◄
    Transistors are Made of Silicon
   Silicon is a grey colored element with crystalline
   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
   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.

   The addition of a small
    amount of a different
    substance to a pure
    semiconductor crystal.
   The impurities give an                          n-type doping
    excess of conducting
    electrons or an excess of
    conducting holes which is
    crucial for making a
    working transistor.

                                                     p-type doping   ◄
                         Donor doping

                         Acceptor doping


                                                                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.

                       Conduction Band
                           Valence Band

Energy Gap: Is
the energy               Conduction Band
difference                                                            Semiconductors
between the                                        Energy gap
valence gap and            Valence Band
the conduction

                         Conduction Band

                                               Bigger Energy gap       Insulators
                          Valence Band

    Valence Band: Is a part of the molecule, called band, where you can find the
                                     electrons                                      ◄
      Transistor types

 MOS - Metal Oxide Semiconductor
 FET - Field Effect Transistor
 BJT - Bipolar Junction Transistor

             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.

                                                ◄   ◄
              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

              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,
                                                     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.“
fundamental/nrc-nint_moleculartransistor_e.html                                        ◄
       Pictorial History of Transistors   ◄
              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.
   You can find two very cool games on transistors in the next link:
    tro.html                                                                 ◄

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