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https://designers-guide.org/forum/YaBB.pl Modeling >> Semiconductor Devices >> depletion width https://designers-guide.org/forum/YaBB.pl?num=1063542138 Message started by Jason_class on Sep 14th, 2003, 5:22am |
Title: depletion width Post by Jason_class on Sep 14th, 2003, 5:22am Hello All , May I know why the depletion width for n side of a pn junction is longer than that of the p side? Also why is the p(x) for n side smaller than that of pside? Kindly let me know which formula I should refer to? Thank you rgds and thanks jason_class |
Title: Re: depletion width Post by Geoffrey_Coram on Sep 16th, 2003, 3:15pm Jason - If the dopant density (which I think you are calling p(x)) is smaller on the n side, then this forces the depletion width to be larger on the n side. It's simple math: the depleted charge on either side must be equal (at equilibrium), and the depleted charge is the density times the volume. Assuming equal cross-sectional area, you're left with the depletion width. As to why n doping is less than p doping, this is process-specific. One could build an (n)(p+) diode or an (n+)(p) diode, ie, with either side more highly doped than the other. I don't know if there's a reason that diodes would typically be doped stronger on the p side. |
Title: Re: depletion width Post by jason_class on Sep 18th, 2003, 9:05am Thanks a lot Geoffrey. You are very helpful rgds and thanks Jason |
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