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Deposition and process control|15 Article(s)
Studies on properties of YbF3 thin film by different deposition parameters
Yaoping Zhang, Hong Zhou, Junqi Fan, and Hong Xu
YbF3 is proposed as a substitute for ThF4 in anti-reflection or reflection coatings in the infrared (IR) range. In this letter, we study on the properties of the YbF3 thin film deposited with different deposition parameters, and find the deposition rate of YbF3 has a large effect on the substrate particles deposition both on number and area. Moreover, we find the deposition temperature is a main factor of element content. In the end, we produce an anti-reflection coating on Ge substrate, and its average transmission reaches 99.5%, which can satisfy the practical requirement. YbF3 is proposed as a substitute for ThF4 in anti-reflection or reflection coatings in the infrared (IR) range. In this letter, we study on the properties of the YbF3 thin film deposited with different deposition parameters, and find the deposition rate of YbF3 has a large effect on the substrate particles deposition both on number and area. Moreover, we find the deposition temperature is a main factor of element content. In the end, we produce an anti-reflection coating on Ge substrate, and its average transmission reaches 99.5%, which can satisfy the practical requirement.
Chinese Optics Letters
- Publication Date: Jun. 07, 2013
- Vol. 11, Issue s1, S10215 (2013)
SiOx protective f ilm thermally evaporated downwards for 2-m level primary mirror
Wenjun Pei, and Hongxiang Liu
The service life of the large primary mirror with aluminum coating can be effectively prolonged by a protective layer. The SiOx (1<x<2) protective material which is thermally evaporated from up to bottom is studied. Environmental adaptability experiment, spectral measurement and micro-morphology analysis are executed on bare SiOx coatings within different oxygen concentrations, and the repeatability verification is implemented by testing the SiOx protected aluminum coatings. The results show that the SiOx coatings can meet the protective qualification within oxygen flow of 50 sccm (p=5.6 \times 10-3 Pa). The fine compactness of the coating has excellent moisture resistance with the average molecular spacing of 0.335 nm. In addition, the average reflectivity of the SiOx protected aluminum coating is 90.47% in the band 400 -2 500 nm and the coating is confirmed to have good environmental performance. The service life of the large primary mirror with aluminum coating can be effectively prolonged by a protective layer. The SiOx (1<x<2) protective material which is thermally evaporated from up to bottom is studied. Environmental adaptability experiment, spectral measurement and micro-morphology analysis are executed on bare SiOx coatings within different oxygen concentrations, and the repeatability verification is implemented by testing the SiOx protected aluminum coatings. The results show that the SiOx coatings can meet the protective qualification within oxygen flow of 50 sccm (p=5.6 \times 10-3 Pa). The fine compactness of the coating has excellent moisture resistance with the average molecular spacing of 0.335 nm. In addition, the average reflectivity of the SiOx protected aluminum coating is 90.47% in the band 400 -2 500 nm and the coating is confirmed to have good environmental performance.
Chinese Optics Letters
- Publication Date: May. 21, 2013
- Vol. 11, Issue s1, S10214 (2013)
Geometry optimization in planetary rotation stage for thickness uniformity of films on spherical substrates
Cunding Liu, Chun Guo, Mingdong Kong, and Bincheng Li
We report the simulation results on the thickness uniformity of optical coatings deposited on spherical substrates by optimizing the geometric configuration parameters, such as tilting angle of the substrate holder and position of the evaporation source in a 1 000-mm-diameter planetary rotation stage (PRS). We reveal that good film uniformity on convex spherical surfaces or flat substrates, as well as concave surfaces with weak to moderate curvatures can be obtained through appropriate tilting of the substrate holder. For 300-mm-diameter substrates with clear aperture to radius of curvature (CA/RoC) between -0.3 and 0.7, the achievable film uniformity is above 99%. The source position is optimized to achieve good film uniformity. We report the simulation results on the thickness uniformity of optical coatings deposited on spherical substrates by optimizing the geometric configuration parameters, such as tilting angle of the substrate holder and position of the evaporation source in a 1 000-mm-diameter planetary rotation stage (PRS). We reveal that good film uniformity on convex spherical surfaces or flat substrates, as well as concave surfaces with weak to moderate curvatures can be obtained through appropriate tilting of the substrate holder. For 300-mm-diameter substrates with clear aperture to radius of curvature (CA/RoC) between -0.3 and 0.7, the achievable film uniformity is above 99%. The source position is optimized to achieve good film uniformity.
Chinese Optics Letters
- Publication Date: May. 29, 2013
- Vol. 11, Issue s1, S10213 (2013)
Effect of high-temperature ablation on protective coating of ZnS optical windows
Kewen Zhuang, Yiqin Ji, Peng Sun, Jian Leng, Yuzhe Xing, Dandan Liu, and Huasong Liu
While infrared (IR) hard protective film of ZnS optical window is used in high temperature environment, its optical and mechanical stabilities are the premise of the IR optical system. IR hard protective film is deposited on ZnS optical windows by chemical vapor deposition (CVD), and ablation experiments are done to the maximum temperature the film can endure. The effects of ablation temperature on the optical and mechanical properties of the protective films are investigated by surface profiler, Fourier-transform infrared (FTIR) spectrometry, IR ellipsometer, and Metallographic microscope. It is shown that the optical and mechanical properties of ZnS hard protective film change little before 500 oC, and film refractive index and optical thickness reduce while ablation temperature surpassing 500 oC, forming crater-like ablation structure, which leads to the reduction of film combination significantly. While infrared (IR) hard protective film of ZnS optical window is used in high temperature environment, its optical and mechanical stabilities are the premise of the IR optical system. IR hard protective film is deposited on ZnS optical windows by chemical vapor deposition (CVD), and ablation experiments are done to the maximum temperature the film can endure. The effects of ablation temperature on the optical and mechanical properties of the protective films are investigated by surface profiler, Fourier-transform infrared (FTIR) spectrometry, IR ellipsometer, and Metallographic microscope. It is shown that the optical and mechanical properties of ZnS hard protective film change little before 500 oC, and film refractive index and optical thickness reduce while ablation temperature surpassing 500 oC, forming crater-like ablation structure, which leads to the reduction of film combination significantly.
Chinese Optics Letters
- Publication Date: Jun. 07, 2013
- Vol. 11, Issue s1, S10212 (2013)
Preparation of broadband antireflective coating by sol-gel method
Fengjuan Liu, Shu Zhou, Weiwei Dong, and Xiaodong Fang
A sol-gel method for the preparation of silica coating that varied in refractive index is developed. Silicon dioxide sol is obtained by hydrolysis and co-condensation reactions occurred in acid-catalyzed system. Surface morphology, refractive index, and transmission spectrum of the samples are studied. The results of transmission spectra of single-sided coatings show that the average transmittance of the samples increases about 4% compared with the uncoated one in the spectra range from 400 to 1 200 nm in the case of vertical incidence. For the double-sided coating the maximum transmittance is 99% at the wavelength of 840 nm. A sol-gel method for the preparation of silica coating that varied in refractive index is developed. Silicon dioxide sol is obtained by hydrolysis and co-condensation reactions occurred in acid-catalyzed system. Surface morphology, refractive index, and transmission spectrum of the samples are studied. The results of transmission spectra of single-sided coatings show that the average transmittance of the samples increases about 4% compared with the uncoated one in the spectra range from 400 to 1 200 nm in the case of vertical incidence. For the double-sided coating the maximum transmittance is 99% at the wavelength of 840 nm.
Chinese Optics Letters
- Publication Date: Jun. 14, 2013
- Vol. 11, Issue s1, S10211 (2013)
Study of aluminum coating prepared by PVD used as anti-corrosion in liquid lead-bismuth
Weiwei Dong, Shu Zhou, Ruhua Tao, Zanhong Deng, Xiaodong Fang, and Qunying Huang
Liquid metals-such as lead (Pb) or lead-bismuth (PbBi) are used as reactor core coolants for accelerator driven systems (ADS) proposed for high-level radioactive waste transmutation. Compatibility of steels with liquid PbBi is a key problem because steels are attacked by dissolution of the components in PbBi, so it has to form a stable coating on steel surface. There are many methods to prepare anti-corrosion coatings on steel, such as hot dipping, pack cementation, plasma spaying, and physical vapor deposition (PVD). Compared with other methods, the PVD method is easy to control the thickness of the coating and the obtained coatings are dense which is crucial to the anti-corrosion ability of the coatings. In this letter, PVD aluminum coatings are developed on the surface of T91 steel and different heat-treatment atmosphere is used to adjust the microstructure, aluminum content, and the phase of the coatings. It is found that the coatings have good adherence ability with steel. The aluminum content and the phase of the coating can be adjusted by the heat-treatment atmosphere. Corrosion tests are performed in oxygen-saturated liquid PbBi at 550 oC for 1 000 h, the phase and composition of the coating do not change drastically. All the results indicate that the PVD is a useful method to prepare coatings on the surface of steel used in liquid PbBi. Liquid metals-such as lead (Pb) or lead-bismuth (PbBi) are used as reactor core coolants for accelerator driven systems (ADS) proposed for high-level radioactive waste transmutation. Compatibility of steels with liquid PbBi is a key problem because steels are attacked by dissolution of the components in PbBi, so it has to form a stable coating on steel surface. There are many methods to prepare anti-corrosion coatings on steel, such as hot dipping, pack cementation, plasma spaying, and physical vapor deposition (PVD). Compared with other methods, the PVD method is easy to control the thickness of the coating and the obtained coatings are dense which is crucial to the anti-corrosion ability of the coatings. In this letter, PVD aluminum coatings are developed on the surface of T91 steel and different heat-treatment atmosphere is used to adjust the microstructure, aluminum content, and the phase of the coatings. It is found that the coatings have good adherence ability with steel. The aluminum content and the phase of the coating can be adjusted by the heat-treatment atmosphere. Corrosion tests are performed in oxygen-saturated liquid PbBi at 550 oC for 1 000 h, the phase and composition of the coating do not change drastically. All the results indicate that the PVD is a useful method to prepare coatings on the surface of steel used in liquid PbBi.
Chinese Optics Letters
- Publication Date: Jun. 14, 2013
- Vol. 11, Issue s1, S10210 (2013)
Modelling and optimization of f ilm thickness variation for plasma enhanced chemical vapour deposition processes
Xiuhua Fu, Lin Li, Gibson Des, Waddell Ewan, and Wingo Lv
This letter describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. Results show DLC uniformity of 0.30% over a 200-mm flat zone diameter within overall electrode diameter of 300 mm. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane. This letter describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. Results show DLC uniformity of 0.30% over a 200-mm flat zone diameter within overall electrode diameter of 300 mm. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane.
Chinese Optics Letters
- Publication Date: Apr. 24, 2013
- Vol. 11, Issue s1, S10209 (2013)
2-nm narrow band pass f ilter in standard conf iguration evaporate coating machine
Jingwei Li, R. Goetzelmann, Xiaoyi Wang, Jiangfan Wu, and Chang Xiao
High sophisticated optical monitoring systems like the OMS 5000 from Leyboldoptics are commonly used in vacuum coating system to improve the capabilities and reliability of production processes concerning optical performance and repeatability optics. This letter describes a method to perform high end optical filters with additional backside blocking over a wide spectral range. The direct monitoring with intermittent measurement on a large area rotating substrate holder is used to facilitate a narrow band pass filter of 2-nm half bandwidth at 532 nm and high transmittance together with a complex blocking filter to retard disturbing radiation from the ultraviolet (UV) range to the near infrared range. The machine is an ARES 1 350 coating system with basically standard configuration. High sophisticated optical monitoring systems like the OMS 5000 from Leyboldoptics are commonly used in vacuum coating system to improve the capabilities and reliability of production processes concerning optical performance and repeatability optics. This letter describes a method to perform high end optical filters with additional backside blocking over a wide spectral range. The direct monitoring with intermittent measurement on a large area rotating substrate holder is used to facilitate a narrow band pass filter of 2-nm half bandwidth at 532 nm and high transmittance together with a complex blocking filter to retard disturbing radiation from the ultraviolet (UV) range to the near infrared range. The machine is an ARES 1 350 coating system with basically standard configuration.
Chinese Optics Letters
- Publication Date: May. 10, 2013
- Vol. 11, Issue s1, S10208 (2013)
Online re-optimization of optical filters on a production sputter tool
Stephan Waldner, Patrick Biedermann, and Silvia Schwyn Thony
This contribution presents a magnetron sputter deposition tool with broadband optical monitor and online re-optimization capability for high volume production. The layer termination relies on a comparison of the actually measured reflection spectrum with a pre-calculated target spectrum. Spectra recorded after each deposited layer are analyzed by the re-optimization module and–in case of significant deviations–layer thicknesses and target spectra for the remaining layers are recalculated. This technique significantly improves the performance and reproducibility in case of highly demanding coating designs and is able to correct abnormal production errors in individual layers, which will lead to coating failure without reoptimization. This contribution presents a magnetron sputter deposition tool with broadband optical monitor and online re-optimization capability for high volume production. The layer termination relies on a comparison of the actually measured reflection spectrum with a pre-calculated target spectrum. Spectra recorded after each deposited layer are analyzed by the re-optimization module and–in case of significant deviations–layer thicknesses and target spectra for the remaining layers are recalculated. This technique significantly improves the performance and reproducibility in case of highly demanding coating designs and is able to correct abnormal production errors in individual layers, which will lead to coating failure without reoptimization.
Chinese Optics Letters
- Publication Date: Apr. 19, 2013
- Vol. 11, Issue s1, S10207 (2013)
Selective epitaxial growth of Ge nanodots with ultra-thin porous alumina membrane
Wenbo Zhan, Yourui Huangfu, Xu Fang, Xia Hong, Liang Xia, Xiongbin Guo, and Hui Ye
We demonstrate that ultra-thin porous alumina membrane (PAM) is suitable for controlling of both size and site of Ge nanodots on Si substrates. Ge nanodots are grown on Si substrates with PAM as a template at different temperatures with molecular beam epitaxy (MBE) method. Ordered Ge nanodot arrays with uniform size and high density are obtained at 400 and 500 oC. Spatial frequency spectrums transformed from scanning electron microscopy images through fast Fourier transform are utilized to analyze surface morphologies of Ge nanodots. The long-range well-ordered Ge nanodot arrays form a duplication of PAM at 400 oC while the hexagonal packed Ge nanodot arrays are complementary with PAM at 500 oC. We demonstrate that ultra-thin porous alumina membrane (PAM) is suitable for controlling of both size and site of Ge nanodots on Si substrates. Ge nanodots are grown on Si substrates with PAM as a template at different temperatures with molecular beam epitaxy (MBE) method. Ordered Ge nanodot arrays with uniform size and high density are obtained at 400 and 500 oC. Spatial frequency spectrums transformed from scanning electron microscopy images through fast Fourier transform are utilized to analyze surface morphologies of Ge nanodots. The long-range well-ordered Ge nanodot arrays form a duplication of PAM at 400 oC while the hexagonal packed Ge nanodot arrays are complementary with PAM at 500 oC.
Chinese Optics Letters
- Publication Date: Apr. 19, 2013
- Vol. 11, Issue s1, S10206 (2013)
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