Abstract
Oxidation kinetics for both dry and wet oxidation of epitaxial NiSi 2 (200 nm)/(001)Si samples as well as dry oxidation of polycrystalline NiSi 2 (200 nm)/(111)Si and epitaxial NiSi 2 (600 nm)/(111)Si samples have been studied by transmission electron microscopy. Comparing oxidation kinetics data of 200-nm-thick epitaxial NiSi 2 on (001) and (111)Si, activation energies of the parabolic rate constants are rather close, whereas those for linear rate constants are substantially different. The orientation dependence of the linear activation energies is explained in terms of the total number of available Si atoms for oxidation as a function of the substrate orientation. Oxide growth rate was found to be higher in polycrystalline NiSi 2 /(111)Si samples than that in epitaxial NiSi 2 /(111)Si samples. Strong influence of the grain boundaries of NiSi 2 on oxidation kinetics was observed with the grain boundaries serving as fast paths for oxidation. For dry oxidation of epitaxial NiSi 2 (600 nm)/(111)Si samples, both parabolic and linear activation energies are higher than those of Ni(200 nm)/(111)Si samples. © 1995 American Institute of Physics.