Electron-cyclotron-resonance sputtering apparatus for multilayered optical bandpass filters applicable to wavelength division multiplexing

Journal Article · Mon Nov 01 04:00:00 EST 2004 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.1809128· OSTI ID:20636785

Jin, Yoshito; Shimada, Masaru; Ono, Toshiro ^[1]

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1. NTT Microsystem Integration Laboratories, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan)

A new apparatus for fabricating narrow-bandpass multilayer filters applicable to wavelength-division multiplexing and the development of this apparatus are described. Electron-cyclotron-resonance (ECR) sputtering with two plasma sources is used in the apparatus. The plasma is produced from a mixture of Ar and O{sub 2} gas and, with a metallic target, generates stable 'metal-mode' deposition. That is, the target is sputtered in a metallic state, and this is followed by oxide-film formation, which is enhanced by exposure of the substrate to the ECR plasma. SiO{sub 2} and Ta{sub 2}O{sub 5} films formed by ECR sputter-deposition in metal-mode are suitable for optical multilayer filters because this form of deposition provides surface smoothness, low loss, and stability of refractive index. Uniformity of deposition is good, with variations in thickness over a 200 mm diameter within {+-}0.43% for SiO{sub 2} and {+-}0.27% for Ta{sub 2}O{sub 5}. The refractive indices of the SiO{sub 2} and Ta{sub 2}O{sub 5} films are 1.46 and 2.10 at a wavelength of 1550 nm. Surfaces are very smooth, with typical root-mean-square roughness values of only 0.13 nm for the Ta{sub 2}O{sub 5} film and 0.19 nm for the SiO{sub 2} film. We describe how we deposited multilayered structures consisting of 43 layers on an optical glass substrate, alternately SiO{sub 2} and Ta{sub 2}O{sub 5}, and thus fabricated a narrow-band bandpass filter. We demonstrate a thin full width at half maximum of only 0.224 nm and bandpass filtering uniformity within {+-}0.1% over the whole 100 mm diameter substrate.

• OSTI ID: 20636785
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films Journal Issue: 6 Vol. 22; ISSN 0734-2101; ISSN JVTAD6
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DEPOSITION
ELECTRON CYCLOTRON-RESONANCE
GLASS
OPTICAL FILTERS
PLASMA
REFRACTIVE INDEX
SILICON OXIDES
SPUTTERING
TANTALUM OXIDES
THIN FILMS