Rapid thermal oxidation of silicon in ozone

Rapid thermal oxidation (RTO) of Si in ozone gas is studied at temperatures between 200 and 550 degrees C, and the properties of the resulting ultrath in oxides are characterized using in situ mirror-enhanced reflection Fourie r transform infrared (IR) spectroscopy. Thus, the frequency and intensity o f the longitudinal optical vibrational mode of the Si-O-Si asymmetric stret ching from ultrathin oxide films (< 30 Angstrom) are probed in different pr ocessing environments and related to the oxidation kinetics and interfacial layer properties. The oxidation rate in ozone is found to be comparable to the one in pure oxygen at approximately 200 degrees C higher temperature. Analyses of the oxidation in ozone show a fast oxidation regime followed by a slow one with activation energies of 0.13 +/- 0.01 and 0.19 +/- 0.04 eV, respectively. Two regions are also observed for the oxidation in pure O-2 with activation energies of 0.20 +/- 0.03 eV for the fast oxidation regime and 0.36 +/- 0.04 eV for the slow one. X-ray photoelectron spectroscopy res ults and IR spectral feature frequency shifts suggest that the RTO of silic on in ozone ambient results in a thinner, less-stressed interfacial layer t han the one obtained in pure O-2. Preliminary electrical characterization u sing surface charge analyses indicates that the oxides formed in ozone are of superior quality. (C) 2000 American Institute of Physics. [S0021- 8979(0 0)06411-2].