Bipolar Junction Transistor (PDF)

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					01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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                                 BJT Magic
                                 Bipolar Junction Transistor
                                    How does it work?




01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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                                             Objectives
      • To understand BJT.
      • In order to love someone, you must get to know and
        understand that person.
      • In order to love BJT, you must get to know and
        understand why BJT behaves the way it does.
      • Up, close and personal.
      • …




                                                                                                             IC/BJT -   2
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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             Electron Shells Structure of Elements
      • Silicon has four valence electron




                                                                                                             IC/BJT -   3
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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                         Silicon: Diamond Lattice
      •      Silicon is an insulator (i.e. non-conductive)
      •      Need free electrons to make a conductor

                             Si         Si         Si         Si
                                                                             Perfect valence
                                                                             bonding
                             Si         Si         Si         Si

                             Si         Si         Si         Si

                             Si         Si         Si         Si

                                                                                                             IC/BJT -   4
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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             Electron Shells Structure of Elements
      • Phosphorus has five valence electron




                                                                                                             IC/BJT -   5
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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                                    n-Type Material
      • Negatively charged material
      • Silicon + Phosphorous n-Type Semiconductor


          Si      Si      Si       Si                                      Si       Si      Si         Si

          Si      Si      Si       Si                                      Si       Si      Si         Si
                                               + P                                                e-
          Si     Si       Si       Si                                      Si       P       Si         Si

          Si      Si      Si       Si                                      Si       Si      Si         Si


                                                                                                             IC/BJT -   6
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
EBB1143


                        Shells Structure of Elements
      • Boron has three valence electron




                                                                                                             IC/BJT -   7
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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                                    p-Type Material

      • Silicon + Boron                       p-Type Semiconductor


       Si       Si       Si       Si                                       Si       Si      Si       Si

       Si       Si       Si       Si                                       Si       Si      Si       Si
                                              + B
       Si       Si       Si      Si                                        Si       B       Si       Si

       Si       Si       Si       Si                                       Si       Si      Si       Si


                                                                                                             IC/BJT -   8
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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                                Cross-Section of BJT
                   Base                 Emitter                                      Collector
                  contact               contact                                      contact
     SiO2
                                     n+ emitter
                                                                                      n+ collector
                  p base                                                              plug
                  n collector
                  n+ buried layer

                  p bulk


                                                                                                             IC/BJT -   9
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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                                -ve
                               BJT supply
                                                                                RC
       +ve supply
        attracts e-
                                    e-flow
                                 repels e-
                                                           Simulation
                                                              RB



                                                              VBE > 0.7
                    Base                Emitter                                      Collector
     SiO2
                                            n+
                                   p                                                       n+
                                               n
                                                       n+
                                                   p bulk              ELECTRON FLOW

                                                                                                           IC/BJT -   10
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001
01000110 01000001 01010111 01001110 01001001 01011010 01010101 01000001 01011010 01001101 01000001 01000100 01001001
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                                              Summary
      • Illustrated is the basic concept on the operation of
        BJTs.
      • You can try different conditions on B and E inputs,
        and see what will happen to the electron flow.
      • Your best reference for this material is as listed in the
        syllabus.
      • The Neamen text.




                                                                                                           IC/BJT -   11
01001000 01010101 01010011 01010011 01001001 01001110 01000000 01010101 01010100 01010000 00101111 00110000 00111001

				
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Description: This article will explained the basic of bipolar junction transistor and its type such as PNP and NPN of transistor. The terminal of BJT is base, collector and emitter.