Short Time Annealing of Coevaporated Tungsten Silicide Films

Short time annealing (STA) of coevaporated WSi2 on single-crystal and polycrystalline Si (poly-Si) doped with B, P, and As has been carried out with a graphite resistance heater up to 1200°C for times as short as 3s. STA at 1200°C for 6s resulted in good film homogenization and fine line patterns down to submicron dimensions, which remained intact and well adherent. STA at 1200°C for 6s yielded a silicide resistivity 2 to 3 times lower than furnace annealing at 950°C, 30 min. These two anneals would produce a calculated minimal and equivalent B diffusion in an underlying partially fabricated device. Dopants in the poly-Si of the polycide structure move rapidly through both the poly-Si and the WSi2 for both STA and furnace annealing. The B redistributes throughout the polycide, but the As and P are lost from the WSi2 surface by evaporation. © 1984, The Electrochemical Society, Inc. All rights reserved.