hw11 - ECE 440 Homework XI Fall 2005 Due: Wednesday,...

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ECE 440 Homework XI Fall 2005 Due: Wednesday, October 26, 2005 1. A Schottky barrier is formed between a metal having a work function of 4.2 eV and p-type Si (electron affinity = 4 eV). The acceptor doping in the Si is 5x10 17 /cm 3 . (a) Draw the equilibrium band diagram showing a numerical value for qV o . (b) Draw the band diagram with 0.3 V forward bias with details including the width of the depletion region and other quantities. (c) Repeat part (b) for 2V reverse bias. 2. Assume that a p + -n diode with a uniform cross section area, A, is built with an n region width l smaller than a hole diffusion length ( l < L p ). This is the so-called narrow base diode. Since for this case holes are injected into a short n region under forward bias, we cannot use the assumption δ p(x n = ) = 0 in Eq. 4-35. Instead, we must use as a boundary condition the fact that
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This note was uploaded on 12/01/2011 for the course ECE 440 taught by Professor Staff during the Spring '08 term at University of Illinois, Urbana Champaign.

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