Radiation Diode Detector Doping question.

[venomxx]

I'm reading up on semiconductors and there seems to be a few fundamentals I cannot find answers for if anyone can help?

I understand that n-type substrate is doped with a donor and p-type substrate is doped with an acceptor creating excess electrons and holes. When you put the p-type and n-type together you get a diode with a depletion layer.

My problem comes with radiation detectors. In the paper below it states that a p-type diode (not substrate) is when you dope small amounts of donor impurities into a p-type substrate. Also a n-type diode (not substrate) is when you dope small amounts of acceptor impurities into a p-type substrate. Why dope the n-type with the opposite (p-type) donor? Is this not just undoing the original doping?

So if this is right, you dope the n-portion of a p-n junction with the opposite doping (acceptors) to form an N-type diode?

Paper: "Modeling the instantaneous dose rate dependence of radiation diode detectors" Jie Shie and William E. Simon Med. Phys 30(9), Sept 2003

Please clarify! Any help is appreciated!

 

[venomxx]

This comes close but does not answer my question:
https://www.physicsforums.com/showthread.php?t=383490

 

[venomxx]

Bump! Can anyone provide any help/resources?

 

[Kholdstare]

The most convenient way to make a diode is taking a substrate and doping one side with different polarity.

 

[venomxx]

The most convenient way to make a diode is taking a substrate and doping one side with different polarity.

Thanks for the reply, to clarify:

Do you mean taking an n-type substrate and doping acceptors on one side of the substrate with a high enough concentraton to change the majority carriers from electrons to holes?
Thus you would have a bigger minority carrier concentration on the p-side then just joining n-type and p-type substrates together to form the junction?

 

[Kholdstare]

Minority carrier concentration depends on built-in potential, doping etc.
To make a diode by joining n and p type you have to fuse the junction to make a contact. The high temperature damages the crystal.