646s11hw11g - Problem 7.1 in chapter 7 of Muller...

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ELEG 646 ; ELEG 446 - Nanoelectronic Device Principles Spring 2011 Homework #11 - due Friday, 6 May 2011, in class 1. The emitter current of a p-n-p transistor with α N = α I is 0.5 mA when the emitter-base junction is forward biased and the collector is left open. (hint: use Ebers-Moll equation to obtain equation when I C = 0). When the collector is shorted to the base, the emitter current rises to 25 mA. Use this expression to obtain the α . Calculate h FE and the base-width (W B ) of the transistor assuming a minority carrier diffusion length of 20 µ m in the base and the emitter efficiency to be unity (1). 2. Problem 6.14 (a) in chapter 6 of Muller & Kamins, p. 322 in 3rd edition. Hint: use a simplified Ebers Moll model in which a current generator qG is in parallel with the current generator: ( α F ×I F ). 3.
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Unformatted text preview: Problem 7.1 in chapter 7 of Muller & Kamins, p. 375 in 3rd edition. Hint: for an npn transistor, use Eqns. 7.1.1 with constant base doping, and 7.1.3, and 7.1.4 (simplifies with constant base doping and low level injection). 4. Consider a Si double-gate n-channel JFET with the following parameters: N A = 3 x 10 18 cm-3 , N D = 10 15 cm-3 , a = 2 m, L = 20 m, and Z/L = 5. Assume n = 1000 cm 2 /V-sec and T = 300K. (a) Calculate the built-in voltage, the pinch-off voltage, and the value of the open channel conductance. 5. Problem 8.1 in chapter 8 of Muller & Kamins, p. 422 in 3rd edition. Homework assignments will appear on the web at: http://www.ece.udel.edu/~kolodzey/courses/eleg646s11.html Include your name, due date, assignment number, and course number on each submission....
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