The reactions of oxygen false(O2false) with the clean Si(111) and (100) surfaces have been studied at high temperatures (890°–1150°C) for oxygen pressures between 5×10−5 normaland 5×10−2 normalTorr . The critical conditions involving oxygen pressure and substrate temperature which are necessary for the growth of SiO2 to occur on these Si surfaces have been determined, and are found to be independent of substrate orientation and doping type under the conditions studied. The observed critical conditions for growth are consistent with a theoretical model which focuses on the kinetics of SiO2 cluster growth and on the thermodynamics of the competing etching reaction leading to production of normalSiO . Evidence is presented for epitaxial growth on Si(100) of cubic SiO2 , β‐cristobalite.

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MOS capacitors with a 4.4 nm thick gate oxide have been exposed to gamma radiation from a Co-60 source. As a result, we have measured a stable leakage current at fields lower than those required for Fowler-Nordheim tunneling. This Radiation Induced Leakage Current (RILC) is similar to the usual Stress Induced Leakage Currents (SILC) observed after electrical stresses of MOS devices. We have verified that these two currents share the same dependence on the oxide field, and the RILC contribution can be normalized to an equivalent injected charge for Constant Current Stresses. We have also considered the dependence of the RILC from the cumulative radiation dose, and from the applied bias during irradiation, suggesting a correlation between RILC and the distribution of trapped holes and neutral levels in the oxide layer

The reactions of H2O with the clean Si(111) and (100) surfaces have been studied at high temperatures (890°–1350°C) for H2O pressures between 7×10−5 normaland 4×10−1 normaltorr . The critical conditions involving H2O pressure and substrate temperature which are necessary for the growth of SiO2 have been determined, and are consistent with a thermodynamic model modified to include effects due to H2O dissociation and normalSiO desorption. In addition to clean (active) and SiO2‐normalcovered (passive) surface regions, an intermediate region is observed and is proposed to be related to a thin, nonpassivating SixOyHz film on the Si surface.

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