Semiconductor Doping: Does Impurity Type Matter?

[phjw]

Hi just a quick question, does the type of impurity (as long as its from group 3 or 5 respectively) used in doping a semiconductor matter in terms of its activation voltage or is it just down to the level of doping?

So for instance a would say a silicon semiconductor doped with 1 to 10,000 parts phosphorus, have exactly the same properties as if it was doped with 1 to 10,000 parts arsenic?

Thanks ozzie

 

[phjw]

Anyone? surly it has an easy answer?

 

[HerrProfessor]

To the best of my knowledge (and I'm not a specialist in the field, mind), the classical model of semi-conductors makes no distinction between the specific dopants, provided they're both of either p- or n-type. Thus, two n-type dopants, when added in the same amount, would produce indistinguishable effects.

Note: This assumes, of course, that the dopants contribute the same number of electrons/holes. X number of atoms of this may contribute fewer conduction electrons than X number of this atom; so I'll assume by "parts" that you mean the same number of contributed electrons/holes, not the same number of atoms.

you can appreciate that there are no "absolute truths." I'm sure that as different elements have different electron densities, there will be different effects, but these are only minimal and are not included in the more simple, standard model of extrinsic semi-conductivity. (It would be an interesting problem from the perspective of density-functional theory.)

I wouldn't stake my life or my pension on this answer, but it is logically consistent. I hope this helps!

 

[HerrProfessor]

** To correct myself in the first sentence of that last post-- classical sources regarding doped superconductors make no distinction between ELECTRONS/HOLES. Dopants are distinct. Boron and aluminum contribute different holes, but the holes themselves are non-distinct... Semantics, I know.