Co diffusion and growth of buried single-crystal CoSi2 in Si(111) by endotaxy

At a growth temperature of 800 °C, Co deposited on a Si capping layer exhibits oriented growth on buried CoSi₂ grains on Si(111), a process referred to as endotaxy. This occurs preferentially to surface nucleation of CoSi₂, provided the thickness of the Si cap is less than a critical value of ≊100 nm for deposition rates of 0.003-0.01 nm/s. The steady-state process is modeled using known values of the Co diffusion coefficient and solid solubility in Si, allowing some conclusions to be drawn regarding parameters relevant to CoSi₂ epitaxy. Using this technique, single-crystal continuous layers of CoSi₂ can be formed under a high-quality Si capping layer.