Effect of ion beam etching on the surface roughness of bare and silicon covered beryllium films
Effect of ion beam etching on the surface roughness of bare and silicon covered beryllium films
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DOI：
10.1016/j.surfcoat.2017.01.023
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发表时间：
2017-02-15
影响因子：
5.4
通讯作者：
Zuev, S. Yu.
中科院分区：
文献类型：
--
作者：
Chkhalo, N. I.;Mikhailenko, M. S.;Zuev, S. Yu.
铍具有低密度、高机械刚度和高导热性，易于加工，是最有前途的空间反射镜材料之一，包括在13-30.4 nm波长范围内研究日冕。机械抛光后这种材料表面粗糙度大是其广泛应用的一个障碍。本文以镀在硅衬底上的200 nm厚的铍薄膜和经过抛光的大块铍为材料，研究了离子束蚀刻对铍进行光抛光的主要方面。我们给出了有关氖离子能量和入射角对铍薄膜表面粗糙度影响的研究结果。我们测量了腐蚀速率取决于入射角度和氖离子的能量。我们发现400 eV是在+/- 40°入射角范围内确保表面粗糙度平滑的最佳能量。在铍上沉积200 nm的非晶硅薄膜，然后用800 eV的氩离子蚀刻，在0.025-60 μ m（-1）的空间频率范围内，从sigma(eff) = 1.37 nm到sigma(eff) = 0.29 nm，提高了有效的表面粗糙度。对沉积在衬底上的Mo/Si反射镜的反射特性的研究结果证实了平滑技术在x射线应用中的有效性。表面粗糙度sigma(eff) = 23 nm（粗糙度值对应于制备的体Be衬底，来源于文献）时，基材在13.5 nm波长处的反射率从2%提高到67.5%。(C) 2017 Elsevier B.V.版权所有
Due to low density, high mechanical rigidity and thermal conductivity, ease of machining beryllium is one of the most promising materials for space mirrors, including for studies of the solar corona in the wavelength range of 13-30.4 nm. An obstacle to the widespread use of this material is its large surface roughness after mechanical polishing. In this paper, using samples of 200 nm thick beryllium films deposited on silicon substrates and polished bulk beryllium, we studied the main aspects of using ion-beam etching for finish polishing of beryllium. We present the results of investigation pertaining to the influence of the neon ion energy and angle of incidence on the beryllium films surface roughness. We measured the etching rates depending on the angle of incidence and energy of neon ions. We found that 400 eV is the optimal energy for neon ion etching ensuring slight surface roughness smoothing in the range of incidence angles of +/- 40 degrees The deposition of 200 nm amorphous silicon films onto beryllium and their subsequent etching with the 800 eV argon ions improve the effective surface roughness integrated across the range of the spatial frequencies of 0.025-60 mu m(-1), from sigma(eff) = 1.37 nm down to sigma(eff) = 0.29 nm. The effectiveness of the smoothing technology for X-ray applications has been confirmed by the results of the study of the reflective properties of the Mo/Si mirrors deposited on the substrate. The reflectivity at a wavelength of 13.5 nm increased from 2% for the substrates with the surface roughness of sigma(eff) = 23 nm (the rough-ness value corresponds to the as-prepared bulk Be substrates and is taken from the literature) up to 67.5% after the smoothing technology. (C) 2017 Elsevier B.V. All rights reserved.