Orbiting solar telescope on “Salyut-4” station

Bruns, A. V.; Grechko, G. M.; Gubarjev, A.A.; Klimuk, P. I.; Sevastjanov, V.I.; Severny, A. B.; Steshenko, N. V.

doi:10.1016/0094-5765(77)90091-1

Cited by 4 publications

(1 citation statement)

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“…The allure of the predicted performance of ideal, non-oxidized Al in the far UV (FUV, 90 < λ < 200 nm) has led to several proposals for the on-orbit fabrication of Al mirrors where the vacuum of space may prevent or slow oxidation. 14,15 Conventional fabrication techniques for Al UV mirrors prevent this oxidation by depositing a protective layer immediately following Al evaporation. These protective layers are typically metal fluoride materials that are transparent at UV wavelengths.…”

Section: Introductionmentioning

confidence: 99%

Enhanced atomic layer etching of native aluminum oxide for ultraviolet optical applications

Hennessy

Moore

Balasubramanian

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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We report on the development and application of an atomic layer etching (ALE) procedure based on alternating exposures of trimethylaluminum and anhydrous hydrogen fluoride (HF) implemented to controllably etch aluminum oxide. Our ALE process utilizes the same chemistry previously demonstrated in the atomic layer deposition of aluminum fluoride thin films, and can therefore be exploited to remove the surface oxide from metallic aluminum and replace it with thin fluoride layers in order to improve the performance of ultraviolet aluminum mirrors. This ALE process is modified relative to existing methods through the use of a chamber conditioning film of lithium fluoride, which is shown to enhance the loss of fluorine surface species and results in conformal layer-by-layer etching of aluminum oxide films. Etch properties were explored over a temperature range of 225 to 300 °C with the Al2O3 etch rate increasing from 0.8 to 1.2 Å per ALE cycle at a fixed HF exposure of 60 ms per cycle. The effective etch rate has a dependence on the total HF exposure, but the process is shown to be scalable to large area substrates with a post-etch uniformity of better than 2% demonstrated on 125 mm diameter wafers. The efficacy of the ALE process in reducing interfacial native aluminum oxide on evaporated aluminum mirrors is demonstrated with characterization by x-ray photoelectron spectroscopy and measurements of ultraviolet reflectance at wavelengths down to 120 nm. IntroductionAluminum possesses a higher ultraviolet (UV) reflectance than other metals like gold and silver due to material properties such as a higher plasma frequency and the absence of strong interband transitions at UV wavelengths. These properties of Al are employed in classical UV optical components like mirrors, 1,2 reflective diffraction gratings, 3,4 and multilayer UV bandpass filters. 5,6 Al is also gaining interest as a plasmonic material for UV applications. The same material properties lead to a wider spectral tunability range for plasmonic effects in Al, 7 and nanostructured Al is being considered for applications like UV resonant biochemical sensors,

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Section: Introductionmentioning

confidence: 99%