Table 1.

Comparisons of Doping Methods (After Plummer et al. [105])

	Ion implantation	Diffusion	Epitaxy
Process condition	room temperature, vacuum, batch process	high temperature, batch process	high temperature, low pressure, single wafer
Damage	significant, requires annealing, enhances diffusion	none	none
Doping concentration control	excellent	acceptable	good
Dopant depth control	good	not good	very good
Typical range of doses or concentration	1×1011 to 1×1016 cm−2	concentration is limited to solid solubility	1×l014 to 1×1017 cm−2
Masking	photoresist or hard mask (silicon oxide, silicon nitride, metal, etc.)	hard mask	oxide mask and selective deposition (more difficult) or etchback