Hafnium oxide (HfO 2 ) and zirconium oxide (ZrO 2 ) are two high-materials having the potential to replace silicon oxide (SiO 2 ) as the gate dielectric. Atmospheric molecular contamination can affect the quality of the new gate dielectric film in a manner similar to SiO 2 . Characterization of contaminant adsorption behavior of these high-films should assist in deciding their potential for successful integration in silicon metal oxide semiconductor technology. The interaction of moisture and organics ͑in particular, isopropanol, IPA͒ as common interfacial contaminants with a 5 nm HfO 2 film deposited by atomic layer chemical vapor deposition ͑ALCVD͒, which is a trademark of ASM International͒ is investigated using atmospheric pressure ionization mass spectrometry ͑APIMS͒; the kinetics and mechanism are compared to that of ZrO 2 and SiO 2 . HfO 2 and ZrO 2 have similar moisture adsorption loading, but are significantly higher than that of SiO 2 . However, almost all the adsorbed moisture can be removed from SiO 2 and HfO 2 after a 300°C bake under nitrogen purge, whereas ZrO 2 surfaces retain 20-30% of the adsorbed moisture. Experiments with IPA show that the adsorption loading on the three surfaces has the following order: ZrO 2 Ͼ HfO 2 Ͼ SiO 2 . A multilayer model for adsorption of water and IPA is developed to understand the mechanism of interactions of contaminants with the three surfaces. Results from the application of this multilayer model to the experimental data indicate that ZrO 2 forms the strongest surfacehydroxyl ͑X-OH͒ bond.

The 1 H NMR spectra of some aqueous dihydroxycholate--cyclodextrin systems show separate 18-CH 3 signals for complexed and free dihydroxycholate ions. The observed variations in line shapes with concentration and temperature were investigated, and kinetic data were derived for both the formation and decomplexation processes. Analysis of the results indicates that, within the concentration range studied, the dominant exchange mechanism involves a unimolecular decomplexation step (dihydroxycholate, -cyclodextrin) f dihydroxycholate + -cyclodextrin. For the chenodeoxycholate system the enthalpies of activation are 43 ( 5 and 45 ( 2 kJ/mol, the entropies of activation are -5 ( 10 and -66 ( 7 J/(K mol) for the formation and decomplexation reactions, respectively, and its decomplexation rate constant is 34 ( 1 s -1 at 300 K. Other dihydroxycholate-cyclodextrin systems show similar activation parameters but slightly lower reaction rates at 300 K. Dehydration plays a major role in the formation process, while the decomplexation rates appear to be controlled by the conformation of the dihydroxycholates.

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Deuterium NMR spectroscopy has been used to probe the dynamics of deuterated octadecylphosphonate (-1,1-d 2 ) (ODPA-d 2 ) monolayers on nonporous ZrO 2 powder (surface area ≈ 40 m 2 /g) over the temperature range of 200-340 K. At 200 K, a broadened Pake doublet with distinct nonrigid characteristics and a horn splitting of approximately 120 kHz was observed. With increasing temperature, the 2 H spectrum gradually transforms into a relatively narrow and featureless peak. Spectral simulations are performed with the help of plausible motional models, and the results show that, over the whole temperature range studied, the C 1 -D bonds have substantial motional freedom with respect to the characteristic 2 H NMR time scale. In addition, at each temperature, a weighted superposition of several simulated line shapes with different rates and site populations is required to account for the observed spectral features, indicating the presence of considerable motional heterogeneity within the ODPA monolayers. The results are further discussed in terms of the known characteristics of the ZrO 2 surface and of the conformational transitions in the octadecyl chain.

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