In-situ studies of silicide formation during growth of molybdenum-silicon interfaces

The growth development of nanometer thick Mo and Si layers was studied using in situ laser deflection and Low Energy Ion Scattering (LEIS). The growth stress obtained from changes in wafer curvature during growth is correlated to changes in the surface stochiometry monitored by LEIS. For Si on Mo, the compressive-tensile-compressive stress development could be explained by the formation of interfacial silicide compounds and the transition between these and the bulk growth of Si. For Mo on Si, a strong initial tensile stress due to silicide formation saturates upon reduced availability of free Si at the growing Mo surface, followed by a near instantaneous tensile increase in stress related to the amorphous-to-crystalline phase transition, which coincides with the end of the compound formation, as determined with LEIS.