Ion implantation
Beginner
Firing atoms of another element into the silicon at high speed. This changes how well that patch carries electricity.
Novice
Dopant atoms such as boron, phosphorus or arsenic are ionized, accelerated (typically 5–200 keV) and shot into the wafer through openings in a mask. A heat treatment (anneal) then repairs the crystal and activates the dopant.
Expert
Dose (ions/cm²) and energy set the amount and depth; the profile peaks below the surface. Channeling along crystal axes is avoided by tilting. Every later hot step moves the profile, so the thermal budget is planned across the whole flow.