The effect of Si/Ir codeposition ratio on the Ir silicide/Si(100) interface roughness

Epitaxial Ir suicide films were grown on p-Si(100) substrates at 450 °C by codeposition of Ir and Si with different Si/Ir atomic ratios. Epitaxial Ir₃Si₄ was grown on Si(100) as pure Ir was deposited at a substrate temperature of 450 °C. The Ir₃Si₄/Si(100) interface remained smooth although intermixing occurred during deposition of Ir on Si(100). Ir₃Si₄ was the phase formed on Si(100) even with higher codeposition ratios, but the Ir₃Si₄/Si(100) interface became rougher at higher codeposition ratios. The interface roughness occurring with higher Si/Ir codeposition ratios was attributed to the spatial inhomogeneity of the Si/Ir ratio on a Si(100) surface during the codeposition. The different degrees of intermixing due to the inhomogeneous surface would make the Ir₃Si₄/Si(100) interface rough. To obtain a sharp interface, deposition of pure Ir on Si(100) at high temperature is suggested.