Download presentation

Presentation is loading. Please wait.

Published byEstevan Linnell Modified over 4 years ago

1
1 Chapter 5-2 Quantitative electrostatic relationships We make the analysis in 1 dimension, even though actual diode as shown may not be a one-dimensional system. This makes the analysis simple. The metallurgical junction is located at x = 0.

2
2 Quantitative analysis: Electric field E p n NANA NDND x p 0x n W E max = q N A x p / = q N D x n /

3
3 Relationship between x n and x p E max = q N A x p / = q N D x n / N A x p = N D x n Net charge on p-side = Net charge on n-side Depletion layer width: W = x n + x p If N A >> N D, then W x n and if N A << N D, then W x p

4
4 Built-in voltage: V bi V bi = {area under E versus x curve} = (1/2) [ W (– q N D x n / ) ] = [q / (2 )] N D x n W

5
5 Quantitative analysis: Electrostatic potential V x V bi

6
6 Step junction with V A 0 The equation for W is similar to the earlier equation except that V bi is replaced by V bi V A ; (V A is restricted to V A < V bi ). V A = Applied Voltage

7
7 Effects of forward and reverse bias

8
8 PN-junction energy-band diagrams

9
9 Example 1 N D = 2 10 16 cm –3 N A = 3 10 17 cm –3 N A = 1 10 16 cm –3 N D = 2 10 17 cm –3 Consider the following diode. Calculate the maximum electric field, E max, the location of E max, the depletion layer width W, x n and x p and the built-in voltage, V bi. Carefully plot the charge density, electric field, and the potential as a function of x. Also, calculate the depletion layer width and the maximum electric field if a reverse voltage of 10 V is applied across the diode. What will be W if V A = 0.5 V?

10
10 Example 2 Consider the diode of Example 1. Calculate the depletion layer width and the maximum electric field if a reverse voltage of 10 V is applied across the diode. Calculate the depletion layer width in the n-side and p-side under this biased condition. What will be W if V A = 0.5 V? What happens if we apply V A > V bi ?

Similar presentations

OK

المملكة العربية السعودية وزارة التعليم العالي - جامعة أم القرى كلية الهندسة و العمارة الإسلامية قسم الهندسة الكهربائية 802311-4 ELECTRONIC DEVICES K INGDOM.

المملكة العربية السعودية وزارة التعليم العالي - جامعة أم القرى كلية الهندسة و العمارة الإسلامية قسم الهندسة الكهربائية 802311-4 ELECTRONIC DEVICES K INGDOM.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google