Formation of ultrathin cosi2 films using a 2-step limited reaction process
Schreutelkamp, Rj × Coppye, W Debosscher, W Vanmeirhaeghe, R Vanmeirhaeghe, L Vanhellemont, J Deweerdt, B Lauwers, A Maex, Karen #
Materials research society
Journal of materials research vol:8 issue:12 pages:3111-3121
The formation of ultrathin (less-than-or-equal-to 20 nm) and smooth CoSi2 layers on c-Si substrates has been studied by using a one- and a two-step RTP silicidation method. Pinhole-free silicide layers with a thickness down to approximately 10-12 nm were formed on n-, n+, and p+ crystalline Si substrates in the one-step RTP process by sputtering of Co films as thin as 4 nm and subsequent silicidation at 750-degrees-C for 5 or 30 s. The two-step RTP silicidation method is based on the consumption of only a small fraction of a thick sputtered Co film to form Co2Si or CoSi during a first RTP step at 400-500-degrees-C. A selective etch follows to remove the unreacted Co film. During a second, higher temperature, RTP step CoSi2 is formed. Pinhole-free and smooth CoSi2 films with a thickness down to 20 nm were formed in this way on both n+ and p+ monocrystalline Si substrates.