EE 5340 Semiconductor Device Theory Lecture 20 - Fall 2010 Professor Ronald L. Carter ronc@uta.edu http://www.uta.edu/ronc

EE 5340 Test 2 – 11 AM – 3Nov 108 Nedderman Hall Procedure as for Test 1 Will cover Chapters 4, 5, and 6. Problems assigned for 4, 5, and 6. Lectures 11 through 20 Cover Sheet draft and Test Instructions will be posted at http://www.uta.edu/ronc/5340/tests/ L20 25Oct2010

npn BJT topology x x’ p-Base n-Collector N-Emitter z WB WB+WC -WE x”c Charge Neutral Region Depletion Region x x’ p-Base n-Collector N-Emitter z WB WB+WC -WE x”c x” xB x’E IE IC IB L20 25Oct2010

IC npn BJT (*Fig 9.2a) L20 25Oct2010

npn BJT bands in FA region q(VbiE-VBE ) q(VbiC-VBC ) qVBE qVBC injection high field L20 25Oct2010

npn BJT regions of operation VBC Reverse Active Saturation VBE Forward Active Cutoff L20 25Oct2010

npn FA BJT minority carrier distribution (Fig 9.4*) L20 25Oct2010

npn RA BJT minority carrier distribution (Fig 9.11a*) L20 25Oct2010

npn cutoff BJT min carrier distribution (Fig 9.10a*) L20 25Oct2010

npn sat BJT minority carrier distribution (Fig 9.10b*) L20 25Oct2010

npn BJT currents (F A region, ©RLC) IC = JCAC IB=-(IE+IC ) JnE JnC IE = -JEAE JRB=JnE-JnC JpE JGC JRE JpC L20 25Oct2010

E current equations mode npn BJT (w/o gen/rec) L20 25Oct2010

C current equations in npn BJT (w/o gen/rec) L20 25Oct2010

Recombination/Generation Currents (FA) L20 25Oct2010

FA npn figure of merit – emitter efficiency L20 25Oct2010

FA npn figure of merit – base transport factor L20 25Oct2010

FA npn figure of merit – recombination factor L20 25Oct2010

Common base current gain, aF aT d L20 25Oct2010

Common base current gain, aF (continued) L20 25Oct2010

Common emitter current gain, bF L20 25Oct2010

References * Semiconductor Physics and Devices, 2nd ed., by Neamen, Irwin, Boston, 1997. **Device Electronics for Integrated Circuits, 2nd ed., by Muller and Kamins, John Wiley, New York, 1986. L20 25Oct2010