Radiation Diode Detector Doping question.

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Discussion Overview

The discussion revolves around the doping processes involved in creating radiation diode detectors, specifically the distinctions between n-type and p-type diodes and the implications of doping methods on semiconductor behavior. Participants explore the fundamentals of semiconductor doping and its application in radiation detection.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that n-type substrates are doped with donor impurities while p-type substrates are doped with acceptor impurities, leading to the formation of a depletion layer when combined.
  • Another participant questions the rationale behind doping a p-type substrate with donor impurities to create an n-type diode, suggesting it may counteract the original doping.
  • A response suggests that the most convenient method to create a diode is to dope one side of a substrate with a different polarity, although the specifics of this process are not fully clarified.
  • Further clarification is sought regarding whether doping an n-type substrate with acceptors would indeed change the majority carriers from electrons to holes, potentially affecting the junction's characteristics.
  • Another participant mentions that minority carrier concentration is influenced by built-in potential and doping levels, and highlights the need for fusing the junction to create a contact, noting that high temperatures can damage the crystal structure.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the doping processes and their implications, with some points of contention remaining about the effects of doping on semiconductor behavior and the methods used to create diodes.

Contextual Notes

There are unresolved questions about the assumptions underlying the doping processes and the effects of high temperatures on crystal integrity, as well as the specifics of how minority carrier concentrations are determined.

venomxx
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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!
 
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Bump! Can anyone provide any help/resources?
 
The most convenient way to make a diode is taking a substrate and doping one side with different polarity.
 
Kholdstare said:
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?
 
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.
 

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