hw60903

# hw60903 - ECE G201 H.W#6 Due 1 A planar silicon diode is...

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ECE G201 H.W. #6, Due March 17, 2009 1. A planar silicon diode is designed as follows: p+ - n junction, with junction depth of 0.5µm from the surface of the wafer, fabricated in an 21micron thick layer of lightly doped silicon (this layer ends 21 microns from the surface) over a very heavily doped silicon substrate (this is the thick silicon substrate). Doping: p+ - 10 18 n - 10 15 n+ substrate - large, you can assume 10 18 but it doesn't matter. Lifetimes: t p = t n = 10 -7 sec T = 300K a. What is the breakdown voltage of the diode, ignoring 3-dimensional effects? (refer to figures in Sze Ch. 2, figures 26, 29, 35. (on web site)) b. What is the breakdown voltage of a square diode of the same doping, (shape as viewed from above) 0.1 cm x 0.1 cm in dimension? (Refer to Fig. 9, Ch. 2, Sze. (on web site)) c. What is the breakdown voltage of a circular diode, again of the same doping, 0.1 cm in diameter? 2. a. Considering only one-dimensional effects, does the onset of series resistance effects, or high injection effects, occur first in this diode? (diode from previous problem, one-dimensional analysis) Estimate the onset of high injection effects as the voltage at which p n at x n = n no . Estimate the onset of series resistance effects by computing the resistivity of the bulk semiconductor, and determining the voltage at which the current is half of that predicted by the ideal diode equation. Examine each effect separately, assuming no other non-ideal effects. T = 300K.

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## This note was uploaded on 03/22/2012 for the course ECE G201 taught by Professor Nm during the Spring '11 term at Northeastern.

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hw60903 - ECE G201 H.W#6 Due 1 A planar silicon diode is...

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