Conformal Deposition of Conductive Single-Crystalline Cobalt Silicide Layer on Si Wafer via a Molecular Approach

Abstract

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 Co-2(CO)(8) with SiH4. Postannealing at 850 degrees C under vacuum (similar to 10(-5) mbar) yields a crystalline CoSi2 film with a lower surface roughness (R-rms = 5.3 nm) by comparison with the conventional physical method; this layer exhibiting a metallic conductive behavior (ohmic behavior) with a low resistivity (rho = 11.6 mu Omega 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.