Professor Ronald L. Carter ronc@uta.edu http://www.uta.edu/ronc/ Semiconductor Device Modeling and Characterization – EE5342 Lecture 18 – Spring 2011 Professor Ronald L. Carter ronc@uta.edu http://www.uta.edu/ronc/

Project Question and Answer What questions pertinent to the project do you have? If questions come up, be sure to see the echo link for the Q&A. ©rlc L18-11Mar2011

Bipolar junction transistor (BJT) E B C VEB VCB Charge neutral Region Depletion Region The BJT is a “Si sandwich” Pnp (P=p+,p=p-) or Npn (N=n+, n=n-) BJT action: npn Forward Active when VBE > 0 and VBC < 0 ©rlc L18-11Mar2011

BJT coordinate systems z x”c x” WB WB+WC -WE xB x x’E x’ Charge neutral Region Depletion Region Base Collector Emitter ©rlc L18-11Mar2011

BJT boundary and injection cond (npn) ©rlc L18-11Mar2011

BJT boundary and injection cond (npn) ©rlc L18-11Mar2011

IC npn BJT (*Fig 9.2a) ©rlc L18-11Mar2011

References 1 OrCAD PSpice A/D Manual, Version 9.1, November, 1999, OrCAD, Inc. 2 Semiconductor Device Modeling with SPICE, 2nd ed., by Massobrio and Antognetti, McGraw Hill, NY, 1993. * Semiconductor Physics & Devices, by Donald A. Neamen, Irwin, Chicago, 1997. ©rlc L18-11Mar2011