HW7_solutions - Homework 7 1. Problem: (a) Consider an...

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1. Problem: (a) Consider an n-channel MOSFET with uniform channel doping with N A =3 × 10 17 cm - 3 and having an oxide 10 nm thick. Calculate the sub-threshold slope at 300 K. (b) Assume now that the Si-SiO 2 interface is not ideal, but there are interface traps with density N it = 10 12 cm - 2 /eV . What is the sub-threshold slope in this case? Solution: (a) On lecture notes Part 3, the subthreshold slope is given by Eq. (280) S = k B T e ln (10)(1 + C D C ox ) (1) where C D = ± s W D,max and W D,max is the maximum depletion width de±ned by Eq. (221) W D,max = ± 4 ± s k B Tln ( N A /N i ) e 2 N A ² 1 / 2 = 61 . 5 nm (2) and C D = 11 . 7 × 8 . 854 × 10 - 12 F/m 61 . 5 × 10 - 9 m =0 . 0017 F/m 2 , (3) and C ox = ± ox t ox =0 . 0034 F/m 2 . Inputting the above values and ±nally we can get the sub-threshold slope S =0 . 0892 . (b) When the Si-SiO 2 interface is not ideal with an interface traps density N it = 10 - 12 cm - 2 , the subthreshold slope is calculated using Eq. (282) S = k
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This note was uploaded on 09/13/2010 for the course ECE ECE344 taught by Professor Polizinni during the Spring '10 term at University of Massachusetts Boston.

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HW7_solutions - Homework 7 1. Problem: (a) Consider an...

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