Shallow source/drain extensions for deep submicron MOSFETs using spin-on-dopants

Spin-on-dopants and rapid thermal processing have been used to form ultra-shallow n⁺-p junctions with metallurgical junction depths as shallow as 12 nm as determined by secondary ion mass spectroscopy. The electrical junction depth and the total charge concentration have been measured in the vicinity of the junction using electron holography and are shown to be consistent with activation efficiencies of 80%. The ultra-shallow junctions have been used as the source and drain contacts of sub-100-nm gate length MOSFETs. From electrical measurements, the authors extract a lateral diffusion length for the source and drains that is comparable to the vertical extent of the n⁺-p junctions.