This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: ECE 440 Homework VII Fall 2008 Due: Monday, October 20, 2008 1. An abrupt Si pn junction has N a = 6x10 16 /cm 3 on the pside and N d = 2x10 17 /cm 3 on the n side. (a) Calculate the Fermi level positions at 300 K in the p and n regions. P region: (1) eV n p q kT E E i f i 394 . 10 5 . 1 10 6 ln 0259 . ln 10 16 = = = N region: (2) eV n n q kT E E i i f 425 . 10 5 . 1 10 2 ln 0259 . ln 10 17 = = = (b) Draw an equilibrium band diagram for the junction and determine the contact potential V o from the diagram. First draw the Fermi level straight across (the sample is in equilibrium). Then, draw E c and E v in both the p and n regions based on the calculations in part (a). V can be determined graphically by summing (1) and (2). (3) eV qV 819 . 425 . 394 . = + = (c) Compare the results of part (b) with V o as calculated from Eq. (58). (4) ( 29 V n N N q kT V i A D 819 . 10 5 . 1 10 6 10 2 ln 0259 . ln 2 10 16 17 2 = = = (58) As you can see, the results in part (b) and (c) are identical. As an exercise, try deriving As you can see, the results in part (b) and (c) are identical....
View
Full
Document
This note was uploaded on 02/22/2010 for the course ECE 440 taught by Professor Lie during the Fall '09 term at University of Illinois at Urbana–Champaign.
 Fall '09
 Lie

Click to edit the document details