Chlorine distribution in the SiO2-Si system has been studied for two types of Cl-doped oxides, both formed at 900~ (i) thermal oxide grown with a trichloroethane (TCA) additive at 1.0, 2.5, and 4.0 equivalent percent HC1 and (ii) low pressure chemical vapor deposition (LPCVD) oxide, produced by the reaction of SiH2Cl~ and N20 at low pressure. Using SIMS profiles, it was found that C] introduced by TCA oxidation piles up at the interface, reaching a peak of 4-10E18 atom/cm 3. This C1 level proved adequate for metal oxide semiconductor (MOS) device passivation of alkali contamination. Conversely, LPCVD oxide deposited over 1000A SiO2 generates a uniformly high C1 level across the deposited oxide (7-10E19 atom/cm3), but very low concentration at the silicon interface (< 1El8 atom/cm3). Only after a high temperature anneal (1000~ for lh) does this level become similar to the TCA value. However, such a treatment conflicts with the present trend toward reduced temperature processing. Since MOS stability is mainly dependent on interface properties, this behavior suggests that TCA oxidation is more effective than LPCVD for alkali contamination control in MOS integrated circuits fabrication.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 137.99.31.134