alloys is faster than that of Fe-5OCr alloy. All of the loops formed at temperatures ranging from 573 K to 973 K, even in the (o+ a + a') phase regions in thermal equilibrium, have moir6 fringe contrast due to precipitates identified as a' phase. The contrast is very weak in the Fe-5OCr alloy because of coarse distribution of precipitates, while the a' phase formed in low purity alloys has somewhat larger interplanar spacings that are modified by interstitial impurities. The a' phase formation on the loops can be understood by radiation-induced segregation of chromium and interstitial impurity atoms.

We investigated the resistance of a low-k SiOCH film structure to plasma-irradiation damage by comparing films deposited by neutral-beam enhanced chemical-vapour-deposition (NBECVD) and conventional plasma CVD techniques to clarify the degradation mechanism of the dielectric constant in low dielectric SiOCH film during plasma etching. We found that the durability of a low-k SiOCH film structure to plasma irradiation strongly depended on the kind of Si–O structure the film had. In particular, a linear Si–O structure was less affected by plasma exposure than were network/cage Si–O structures because of the small amount of stress in the O–Si–O structure. In addition, this linear Si–O structure helped to reduce the number of methyl groups removed from the film by plasma irradiation, which preserved the dielectric constant. Since the NBECVD technique can generate a low-k SiOCH film with more linear Si–O structures than conventional plasma CVD, a film made through this technique has very strong plasma durability.

To precisely control the dielectric constant and the structure of a low-k SiOC film, we have developed a neutral-beam-enhanced chemical vapour deposition (NBECVD) method. Using Ar NBECVD, we can precisely control the dielectric constant and the film modulus of low-k SiOC deposited on Si substrates because this method avoids precursor dissociation that results from electron collisions and UV photons in plasma. Optimizing the ratio between Si–O and Si–(CH3)x as well as the proportions of linear (two-dimensional SiOC), network and cage (three-dimensional SiOC) structures by changing the precursor, we obtained a k value of 2.2 and a reasonable modulus by using dimethyl dimethoxy silane as a precursor. Additionally, the NBECVD process is applicable as a method for damage-free super-low-k film deposition on the underlying low-k film that is sensitive to damage by the plasma.

Infrared absorption measurements at normal incidence of radiation have been carried out on octadecanethiol (ODT) deposited from ethanol-water mixed solutions onto colloidal silver particles (ca. 30 nm diameter) on Si(111) substrates. The infrared absorption spectra taken as functions of silver mass thickness and ODT concentration show that the intensities of the CH 2 asymmetric and symmetric stretch modes of ODT are twice enhanced in comparison to those observed in the absence of the particles. The spectra also reveal that at any ODT concentration the absorption intensities exhibit a maximum for a particular mass thickness of the particles, indicating that the enhancement is linked to the aggregation of the particles. Contribution of the surface plasmon resonance apparently does not play a major role in the present systems. Approximately the same magnitude of enhancement is obtained for silver hydrosol particles exposed to ODT from the solution followed by depositing on the substrates. Scanning electron morphological inspection has been done on the aggregates in relation to the enhancement.

We developed a neutral-beam-enhanced method of chemical vapour deposition (NBECVD) to obtain a lower dielectric constant for the SiOCH interlayer dielectric film while maintaining a reasonable modulus. We achieved a higher deposition rate than that with the precursor of dimethyl-dimethoxy-silane (DMDMOS) we previously reported on by using Ar NBECVD with a precursor of dimethoxy-tetramethyl-disiloxine (DMOTMDS). This is because of the high absorption coefficient of DMOTMDS. Ar NBECVD with DMOTMDS also achieved a much lower dielectric constant than the conventional PECVD film, because this method avoids the precursor dissociation that causes low dielectric film with many linear Si–O structures. We obtained a k value of 1.9 for the super-low-k SiOCH film with an extremely water resistant, and very thermally stable and integration-possible modulus (>4 GPa) by controlling the bias power.