The atomic scale structure and its dependence on Pt concentration of a Pt-doped SnO 2 (Pt/SnO 2 ) thin film produced by a sputter-deposition method was investigated，which showed a high-performance methane gas sensor. Extended X-ray absorption fine structure (EXAFS) and X-ray diffraction (XRD) analyses showed that Pt/SnO 2 has a rutile structure similar to SnO 2 crystals at less than 10 at% Pt where the Pt ion was located at the Sn position in the rutile structure. There was no evidence that Pt metal clusters were formed in the Pt/SnO 2 films. The Pt/SnO 2 structure became amorphous at greater than 11 at% Pt. We found a good correlation between the methane activity and local structure of Pt.

Polishing and the polishing mechanism are studied for low dielectric constant SiOC layer deposited by plasma-enhanced chemical vapor deposition ͑PECVD͒. Hardness changed from 4.6 to 13.4 GPa with varying carbon content from 0.35 to 0.50. Good barrier performance was attained for the copper diffusion in layers with carbon contents above 0.35 when annealed at 400°C. Removal rate in mechanical polishing decreased, inversely proportional to the hardness as given theoretically. However, removal rate was weakly dependent on the hardness in the chemical polishing by the MnO 2 slurry. Higher removal rate is fulfilled by this chemical polishing.The reduction of CR time constant in multilayer interconnections can be fulfilled by employing low dielectric constant interlayers. Therefore, development of advanced low dielectric constant interlayers has become more important. A plasma-enhanced chemical vapor deposition ͑PECVD͒ SiOC layer is a promising low dielectric constant interlayer because the conformal layer can be deposited by conventional PECVD reactor. However, few papers have reported the deposition and properties of this interlayer. Chemical mechanical planarization ͑CMP͒ processing has been extensively used for planarization in the Cu/low dielectric layer damascene process. A polishing stopper of CVD Si 3 N 4 layer was applied during CMP. Hardness was as high as 15.0 GPa and lower removal rate was accomplished by Si 3 N 4 layer. Development of lower dielectric constant polishing stopper is required for the reduction of CR time constant in the copper interconnection. 1 This layer is also likely to be a good diffusion barrier layer for the copper diffusion.To establish a CMP process for these layers, the polishing mechanism for CVD SiOC layer must be studied. However, polishing of this layer has not been reported. This paper describes the polishing mechanism in mechanical and chemical polishings in CVD SiOC layer with different carbon contents. Hardness and removal rate in the mechanical polishing varied with this change of carbon content. ExperimentalLow dielectric constant SiOC interlayer 500 nm thick was deposited on p-Si͑100͒ wafers at 375°C, where dual-frequency plasmas ͑13.56 MHz and 380 kHz͒ were used in the deposition by PECVD. Hexamethyldisiloxane ͑HMDSO͒ and CH 4 gas were used as the source gas. The carbon content of the SiOC layer was controlled by varying the CH 4 flow rate from 0 to 300 sccm, while the flow rate of HMDSO was held at 50 sccm. The layers were polished with a ring-type polishing machine at a rotational speed of 30 rpm and 300 g/cm 2 employing a Suba-600 pad. The diamond dresser was used for the dressing. Commercially available fumed silica ͑par-ticle size 0.1 m, pH 10.6͒ and newly developed MnO 2 slurries ͑particle size 0.4 m, pH 8.6͒ were used for these polishings. The polishing mechanism was studied by compositional analyses of the thin surface layer formed by the reaction with slurry employing X-ray photoemission spectroscopy ͑XPS͒.

This paper describes section topography using an X‐ray microbeam and a novel slit having a V‐shaped crevice (V‐slit). The V‐slit is characterized by a sharp‐pointed exponential transmission curve, which enables depth‐resolved imaging with high spatial resolution. An iterative deconvolution for image restoration is effectively executable, providing submicron resolution in cross‐sectional diffraction imaging. The new method is applied to the analysis of screw dislocation in a SiC diode. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

No abstract

This paper is focused on evaluating the dominant factor for electromigration (EM) in sputtered high purity Al films. A closed-form equation of atomic flux divergence by treating grain boundary diffusion and hillock formation in a polycrystalline structure without passivation layer was derived to construct the theoretical model. According to the developed equation, it is available to see the effect of various parameters on the EM resistance. Moreover, based on the proposed model, we compared the EM resistance of different sputtered high purity Al films. These films differ in purity and features, which are realized as affecting factors for the EM resistance. Finally, according to the analysis by the synthesis of the obtained EM resistance, the evaluation of the dominant factor for EM in sputtered high purity Al films was approached. Although the effects of the average grain size and the effective valence cannot be ignored, the difference in diffusion coefficient was believed to have a dominant influence in determining the EM resistance. Thus, increasing the activation energy for grain boundary diffusion can significantly reduce the damage during EM in such sputtered polycrystalline Al films.