INVESTIGATION OF THE OXIDATION-KINETICS OF COSI2 ON (111)SI BY TRANSMISSION ELECTRON-MICROSCOPY

Transmission electron microscopy has been applied to study oxidation k inetics of CoSi2 on silicon for both dry and wet oxidation. Care was t aken to determine the activation energies of oxidation in the temperat ure and time regime where the islanding of CoSi2 does not occur. For d ry oxidation, activation energies for parabolic and linear growth were found to be 1.91 and 2.01 eV (+/- 0.1 eV), respectively. For wet oxid ation, activation energies for parabolic and linear growth were found to be 1.75 and 1.68 eV (+/- 0.1 eV), respectively. The activation ener gy of the parabolic rate constant is substantially different from thos e obtained previously. The difference is attributed to the occurrence of islanding during oxidation in the previous study. A comparison of o xidation kinetics of CoSi2, NiSi2, TiSi2 on silicon with pure silicon substrates indicated that the oxidation kinetics are practically the s ame for CoSi2 and NiSi2 in the parabolic growth regime, but substantia lly different from those of TiSi2 on silicon and pure silicon. The sim ilarity in oxidation kinetics of cubic CaF2 structure CoSi2 and NiSi2 on silicon with small mismatches to silicon is correlated to essential ly the same stress level in these two silicides during the oxidation.