Poly(phenylsilsesquioxane) with molecular weight of 1400 was synthesized by hydrolysis of phenyltrichlorosilane, followed by condensation of the resulting hydrolyzates in the presence of a catalytic amount of hydrochloric acid in methyl isobutyl ketone. The progress of dehydration of the hydrolyzates leading to poly(phenylsilsesquioxane) was monitored by 29 Si NMR spectroscopy. Dehydration of cis-(1,3,5,7-tetrahydroxy)-1,3,5,7-tetraphenylcyclooctasiloxane as a model compound was also investigated by the 29 Si NMR technique. The mechanism for the formation of poly(phenylsilsesquioxane) is discussed.
PACS. 81.15.Hi -Molecular, atomic, ion, and chemical beam epitaxy. PACS. 68.65.-k -Low-dimensional, mesoscopic, and nanoscale systems: structure and nonelectronic properties. PACS. 78.67.Lt -Quantum wires.Abstract. -An original mechanism is described for the self-assembly of nanometer-sized structures in the silicon germanium material system. The self-organized formation of vertical Si-rich quantum wells (VSQW) is obtained during the growth of Si1−xGex on narrow line-shaped Si mesa, which are oriented in 150 on the Si (001) surface. The occurrence of the VSQW is accompanied by the formation of {15 3 23} facets on top of the mesa. Detailed structural insights have been gathered by cross-sectional transmission electron microscopy, secondary electron microscopy and photoluminescence measurements. Ge quantum wires are embedded into the VSQW forming a superlattice containing SiGe and Ge wires. Intense low-temperature photoluminescence, which can be assigned to this one-dimensional superlattice, has been observed.
Most of positive chemical amplification resists do not have enough stability to process delay. It has been claimed that airborne contaminants neutralize acids from photo-acid generators. It has been found by means of X-ray photoelectron spectroscopy that an onium salt used as a photo-acid generator is deficient at the surface of the prebaked resist film. The over-top coating using water-soluble polymers with organic acids has been investigated in order to not only separate the resist surface from airborne contaminants but also supply acids to the resist surface. We have succeeded in the suppression of the surface insoluble layer generation and of the pattern size change for more than 8 hours.
Thermal decomposition of spin-coated films of partly protected polyvinylphenol with the t-butoxycalbonyl ( tBOC-PVP) group has been investigated by monitoring the intensity of the carbonyl stretching peak of the tBOC group by using temperature-variable time-resolved infrared spectroscopy (TR/IR). The temperature programming method has been used for determining the activation energy ( Ea) of the thermal decomposition. We compared the thermal decomposition behavior of tBOC-PVP films with that of the powders and the behavior of a 22% protected tBOC-PVP film with that of a 66% protected tBOC-PVP film. It was found that the Ea of the 22% protected tBOC-PVP film is distinctively higher than the others including the result given from thermogravimetric analysis (TG). In addition, the Ea of the 22% protected tBOC-PVP film increased up to 50 kcal/mol with the decrease of the remaining tBOC group, while the others were constant at 30 kcal/mol. Diglyme, which was used as the solvent in the 22% protected tBOC-PVP film, was residual after the temperature increased above 80 °C, and the reaction velocity of the tBOC group increased in accordance with the generation of the OH group. These results suggest that the OH group, which accelerates the thermal decomposition of tBOC-PVP, is hindered by the residual solvent in the case of the 22% protected tBOC-PVP films.
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