[Chem. Mater.] Conformal Deposition of Conductive Single-Crystalline Cobalt Silicide Layer on Si Wafer via a Molecular Approach
Collaborative work led by the Copéret group. New method to prepare high-quality CoSi films.
The realization of metal-semiconductor contacts plays a significant role in ultrascaled integrated circuits. Here, we establish a low-temperature molecular approach for the conformal deposition of a 20-nm Co-rich layer on Si (100) wafers by reaction in solution of Co2(CO)8 with SiH4. Post-annealing at 850 °C under vacuum (~10-5 mbar) yields a crystalline CoSi2 film with a lower surface roughness (Rrms=5.3 nm) by comparison with conventional physical method; this layer exhibiting a metallic conductive behavior (Ohmic behavior) with a low resistivity (ρ =11.6 μΩ.cm) according to four-point probe measurement. This approach is applicable to trench-structured wafers, showing the conformal layer deposition on 3D structures and showcasing the potential of this approach in modern transistor technology.