Published online by Cambridge University Press: 22 February 2011
The electrical properties of shallow P+/N junctions formed by boron outdiffusion from polycrystalline and epitaxial CoSi2 contacts are discussed. The CoSi2 contacts are grown on (100) Si from a sputtered metal layer by rapid thermal annealing (RTA) at 900°C in forming gas. The epitaxial CoSi2 (epi-CoSi2) is made from layers of 15 nm Co / 2 nm Ti, and the polycrystalline material (poly-CoSi2) is made from a 15 nm Co layer with no Ti. Dopant is introduced by ion implantation into the silicide and the P+/N junctions are formed by a second RTA step. Junctions are found to have total leakage current densities as low as 4 nA/cm2 for poly-CoSi2 and 12 nA/cm2 for epi-CoSi2 at -5V and metallurgical junction depths of 60 nm beyond silicide/Si interface after 700-800°C annealing.