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Unformatted text preview: ELEG 646 ; ELEG 446 Nanoelectronic Device Principles Spring 2011 Homework #8  due Friday, 15 April 2011, in class 1. A. symmetrical abrupt Ge pn junction has dopant concentrations of 10 15 atoms cm3 on both sides. Calculate the avalanche breakdown voltage if the maximum field at breakdown is 2.5 x10 5 V/cm. Hint: Careful to use Ge materials data rather than Si. 2. In the problem (1) above for Ge with doping impurity concentration N I = 10 15 cm3 , compare your breakdown voltage with the value obtained by using the following universal (but approximate) expression breakdown voltage for materials with different bandgaps: BV(volts) = 60(Eg/1.1) 3/2 (N I /10 16 )3/4 . Here E g is in eV, and N I is in cm3 . Is this universal expression useful? 3. Problem 4.13 in chapter 4, Muller & Kamins, p. 224 in 3rd edition. Hint: In the discussion following Eq. 4.4.20, there is a discussion in the text of current (10 mA), atomic density (5E22 cm3 ), etc. Use the data and the equations in this section to determine the tunneling probability, then work back to find the L,...
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This note was uploaded on 12/02/2011 for the course ELEG 646 taught by Professor Staff during the Spring '08 term at University of Delaware.
 Spring '08
 Staff

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