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How pin diode works?

I dont't understand how pin diode reach the equilibrium state...
I can consider the pin diode as a duble junction p-i and i-n (with
ideal intrinsic layer without any dopant). First i consider only the p-
i junction...when the two parts are in contact, holes move for
diffusion from p-semiconductor to i-semiconductor, but ionized
dopants make drift curruent...so the equilibrium is reached when the
two components are equal. The equilibrium condition make the equation
NaXp=NiXi, but Ni=0 (ideal condition) so Xi tends to infinite. What
means? holes are placed all along the i-semiconductor?
If consider i-n junction the problem is the same....If consider all
pin diode at equilibrium i-region remains intrinsic:why? Because holes
and electrons recombine in i-region or because they reach opposite
iones and recombine with them?
I'm looking for something about,but nothing i've found..
Thants
 
P

Phil Hobbs

Jan 1, 1970
0
I dont't understand how pin diode reach the equilibrium state...
I can consider the pin diode as a duble junction p-i and i-n (with
ideal intrinsic layer without any dopant). First i consider only the p-
i junction...when the two parts are in contact, holes move for
diffusion from p-semiconductor to i-semiconductor, but ionized
dopants make drift curruent...so the equilibrium is reached when the
two components are equal. The equilibrium condition make the equation
NaXp=NiXi, but Ni=0 (ideal condition) so Xi tends to infinite. What
means? holes are placed all along the i-semiconductor?
If consider i-n junction the problem is the same....If consider all
pin diode at equilibrium i-region remains intrinsic:why? Because holes
and electrons recombine in i-region or because they reach opposite
iones and recombine with them?
I'm looking for something about,but nothing i've found..
Thants

Think of a PIN diode as an ordinary PN junction with a really really
thick depletion zone. You store a lot of charge there, so it takes
quite awhile for it to be swept out when you apply reverse bias. The
net effect is that the amount of bias current required for a given
linearity level is much reduced.

Cheers,

Phil Hobbs
 
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