Saturation Current Calc: NA, ND, μp, μn, τp, τn for Si p-n Junction

In summary, we are given the values NA=1016 cm-3, ND=1017 cm-3, μp=260 cm2/V·s, μn=1100 cm2/V·s, τp=8*10-7 s, τn=2*10-6 s for a silicon pn junction. We are asked to calculate the saturation current Is for a junction area of A=0.1 mm2. The formula for Is is Is=A.ni2.e / q.wp.wn, where wp and wn are the minority carrier lifetimes for holes and electrons, respectively. We can calculate wp and wn using the equations wp = μp * ni / τp and wn = μn *
  • #1
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Homework Statement


NA=1016 cm-3, ND=1017 cm-3, μp=260 cm2/V·s, μn=1100 cm2/V·s, τp=8*10-7 s,
τn=2*10-6 s is given for a silicon pn junction.
Assume ni=1010 cm-3 and εSi=1.04*10-12 F/cm.

Calculate the saturation current Is for a junction area of A=0.1 mm2.

Homework Equations


i found this picture as a formula but i m not really sure what does wp and wn mean
http://ecee.colorado.edu/~bart/book/book/chapter4/gif/eq4_4_28.gif

any help is appreciated
 
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  • #2
The Attempt at a Solutioni tried to solve it but i m stuck here : Is=A.ni2.e / q.wp.wn wp = μp * ni / τp wn = μn * ni / τn = 0.1* 1010^2 * 1.6 * 10^-19 / ( 1.6 * 10^-19 * ( ? * ? ) )
 

FAQ: Saturation Current Calc: NA, ND, μp, μn, τp, τn for Si p-n Junction

1. What is the significance of NA and ND in the saturation current calculation?

NA and ND represent the acceptor and donor concentrations in the p and n regions, respectively, of the Si p-n junction. These concentrations determine the number of majority carriers (holes in p-region and electrons in n-region) available for recombination, which affects the saturation current.

2. How do the values of μp and μn impact the saturation current?

μp and μn represent the hole and electron mobilities in the p and n regions, respectively. These values affect the rate at which majority carriers can move through the material, and therefore impact the saturation current. Higher mobility values result in a lower saturation current.

3. What is the role of τp and τn in the saturation current calculation?

τp and τn represent the minority carrier lifetimes in the p and n regions, respectively. These values determine the average time that minority carriers (electrons in p-region and holes in n-region) can remain in the material before recombining. A longer minority carrier lifetime results in a lower saturation current.

4. How is the saturation current affected by changes in NA, ND, μp, μn, τp, and τn?

The saturation current is directly proportional to NA and ND, meaning an increase in either of these values will result in a higher saturation current. On the other hand, μp, μn, τp, and τn all have an inverse relationship with the saturation current, meaning an increase in these values will result in a lower saturation current.

5. Can the saturation current be reduced in a Si p-n junction?

Yes, the saturation current can be reduced by adjusting the values of NA, ND, μp, μn, τp, and τn. Additionally, the use of materials with higher mobility and longer minority carrier lifetimes, as well as optimizing the geometry of the junction, can also help decrease the saturation current.

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