How can we dope atoms to make an extrinsic semi-conductor from an intrinsic one? (For example, doping Si with P.)
you can perform doping by two methods
-implantation+ thermal annealing for crystal recovery and dopants activation
-diffusion+ thermal annealing to diffuse the doping impurities in the material
In case of hdrogenated amorphous silicon doping is done by glow discharge of silane gas with phosphene gas for n type and with diborane gas for p type extrinsic semiconductors. Only silane gas discharge produces intrinsic hydrogenated amorphous silicon. This method of doping in amorphous silicon is much simpler than implantationimplantation or diffusion methods used in crystalline silicon for doping. In case of chalcogenide glassy semiconductors doping is done by putting impurity in melt and then quenching to make glass.
You can do ion implantation of the dopant atoms in a high-vacuum chamber and anneal it afterwards.
The method of obtaining the most uniform silicon N-type doping is the nuclear transmutation. It consists in submitting an intrinsic silicon rod to neutrons irradiation that transforms a small amount of the silicon (Si) atoms of the crystal lattice into phosphorus (P) atoms which is an N-type dopant. In practice, intrinsic silicon doesn’t exist, even the purest silicon crystal is P-type, because the native boron contained into the silicon crystal rod cannot be eliminated; therefore a very high resistivity of P-type instead of intrinsic silicon is used. This method is specially used for the fabrication of high voltage, large area, high power silicon rectifiers and silicon controlled rectifiers (SCRs).
The question was answered well by the other specialists. The best way of doping depends on material to be doped. Doping during growth is more frequently used at present.
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