THERMAL-OXIDATION KINETICS OF (100)SILICON AND (111)SILICON IN NITROUS-OXIDE

Thermal oxidation of (100) and (111) silicon (Si) in a nitrous oxide ( N2O) ambient has been studied. The oxidation rate follows a parabolic to linear behavior. The activation energies in the parabolic regime we re found to be 2.02 and 1.54 eV/molecule for (100) and (111) Si, respe ctively. The activation energy for the Linear rate constant is estimat ed to be 1.61 and 1.37 eV/molecule for (100) and (111), Si, respective ly. The limiting mechanism for the parabolic regime is attributed to t he diffusion of oxidant through a surface oxynitride layer. The gradua l shift to linear behavior is unusual and is in direct contrast with t he Grove-Deal model [J. Appl. Phys. 36, 3770 (1965)]. Finally, seconda ry ion mass spectrometry shows a temperature dependent distribution an d concentration of nitrogen at the interface. (C) 1995 American Instit ute of Physics.