I assume that if people are going to the trouble to literally irradiate the material in order to get what they need, they can't get the results by just mixing in phosphorus. Could somebody who actually understands this tell me why that is?
And doping during crystal growth doesn't produce homogenous enough silicon.
It's apparently possible for boron doping.
I think because phosphorus is bigger than silicium you'll get too many defects in the crystal, while with the smaller boron it is not an issue.