Article

Abstract

The solution sol-gel method is used to produce thin films of photosensitive hybrid organic-inorganic glass on silicon. Glasses consisted of photoinitiator, methacryloxypropyltrimethoxysilane, methacrylic acid, and zirconium oxide. Clear, low optical loss films are obtained, indicating nanophase homogeneity in the samples. The nanocomposite films are shown to be suitable for fabricating optical components such as ridge wave guides and Bragg diffraction gratings. The increase in the refractive index of the glass relative to the surrounding material during photolithographic processing is identified as a key material parameter in device fabrication. Accordingly, electronic and vibrational spectroscopy are used to provide insight into the structural changes that occur when glasses are irradiated with continuous narrow band 4.9 eV and pulsed 6.4 eV light. Arguments are advanced, linking the changes in refractive index to collateral densification leading to volume compaction of the silicate network during organic free-radical polymerization. This was shown by following the time evolution of relevant IR absorption bands. Free silanol and unreacted methoxysilane are consumed in the process. Matrix densification is indicated by shifts to low wave number in the transverse optical phonon mode associated with decreasing Si-O-Si bond angles of the antisymmetric stretching vibration (compression). Growth in the Si-O-Si framework is observed through increased intensity in this IR absorption. Similar behaviour is observed for films irradiated with 6.4 eV light from an excimer laser. A phase mask in combination with pulsed 6.4 eV light is used to inscribe a 1.5 mm, high-reflectivity polarization-independent Bragg grating into a ridge wave guide. The high reflectivity is thought to arise from a periodic modulation of the volume compaction of the matrix. Overall, the organic component of the glass confers unique properties on the material that allow it to be densified even with 4.9 eV light. By comparison, sol-gel silica with no organic component must be densified at nearly twice the photon energy.Key words: sol-gel, wave guide, Bragg grating, photochemistry, densification, refractive index, photolithography.

Highly Dispersed Mixed Zirconia and Hafnia Nanoparticles in a Silica Matrix: First Example of a ZrO2–HfO2–SiO2 Ternary Oxide System

“…The bands at 2890 and 2950 cm -1 are due to the asymmetric stretching of m s (CH 3 ) groups and to the symmetric m s (CH) stretching of the terminal methylene double bonds ( CH 2 ), respectively. [8] Accordingly, all these vibrational modes disappeared upon calcinations. The sharp band at 1730 cm -1 is ascribed to the C O carbonyl group.…”

“…[18,49,50] A further band at 450 cm -1 was also detected, which has been ascribed by other authors to the vibrations of the Si-O-Si network. [8] All vibrations typical of the organic components of the matrix could be detected in the as-prepared samples. The bands at 2890 and 2950 cm -1 are due to the asymmetric stretching of m s (CH 3 ) groups and to the symmetric m s (CH) stretching of the terminal methylene double bonds ( CH 2 ), respectively.…”

“…[1,2] Furthermore, both binary ZrO 2 -SiO 2 and HfO 2 -SiO 2 systems are appealing materials for the development of high-j films to overcome limitations in the fabrication of integrated circuits. [3][4][5][6][7] The embedding of guest particles in a transparent and dielectric matrix enables fine tailoring of its optical properties, [8] such as refractive index. In the form of powder these mixed oxides are also attracting a growing interest both as catalysts [9][10][11][12][13] as well as catalyst supports.…”

ビニルトリエトキシシランから作製した無機-有機ハイブリッド厚膜の微細パターニング

“…[5][6][7][8][9][10] For the preparation of planar waveguides, photosensitive inorganic-organic hybrid films prepared by the sol-gel method have been studied extensively. [11][12][13][14][15][16][17][18][19] In these studies on inorganic-organic hybrid films, trimethoxysilylpropylmethacrylate TMSPM has been favored as a precursor since the methacrylate group easily polymerizes under UV irradiation or thermal treatment, 20 and the polymerization leads to an increase of refractive index to control waveguiding. We have reported on the preparation of inorganic-organic hybrid films from vinyltriethoxysilane VTES, allyltriethoxysilane or TMSPM, and zirconium n-tetrapropoxide modified with methacrylic acid, 21 and found that patterns with a width of about 10 mm and thickness of about 15 mm were formed by the etching of unirradiated region of the films.…”

Photoinduced condensation of sol-gel hybrid glass films doped with benzildimethylketal

“…The increase in refractive index of the SGHG films is mainly governed by photopolymerization of the organic component and polycondensation of the inorganic component. 10,11 However, the effect of the photoinitiator which has been usually 1-hydroxycyclohexyl-1-phenylketone (HCPK) sensitive to the light from the UV region on the refractive index change has been ignored since a small quantity of photoinitiator has been used. BDK is a common photoinitiator sensitive to 350 nm light to be used in a general mask aligner.…”