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Your search keyword '"Dashkov, A. S."' showing total 18 results
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18 results on '"Dashkov, A. S."'

14. Blazed Diffraction Gratings on Si --- First Results

Author

null Dashkov A. S., null Pirogov E. V., null Shubina K. Yu., null Sharov V. A., null Mokhov D. V., null Berezovskaya T. N., and null Goray L. I.

Abstract

Using direct laser lithography and wet etching of polished vicinal Si(111) wafers, a technology was developed and diffraction gratings 500 grooves/mm with a blaze angle of 4o were fabricated. The manufacturing process of a reflective Si-grating with the triangular profile (sawtooth) can be divided into four main steps: (1) obtaining a pattern of a protective mask for grooves etching; (2) anisotropic etching of grooves in KOH solution; (3) etching to smooth the grating profile and polish the surface of working facets; (4) coating to increase reflectivity. The samples obtained were characterized using scanning electron microscopy and atomic force microscopy methods to determine the shape of the groove profile and roughness: the shape turned out to be close to the ideal triangular, and the RMS roughness was less than 0.3 nm. Using PCGrateTM software and taking into account the measured real groove profile, the diffraction efficiency of gratings operating in classical and conical mounts in soft-X-ray and extreme ultraviolet radiation has been simulated. The obtained efficiency values are close to the record ones for the corresponding spectral range and the Au-coating of the grating. Keywords: diffraction grating, wet etching technology of Si, sawtooth groove profile, AFM, SEM, diffraction efficiency modelling.

Published
2022

18. Deep X-Ray Reflectometry of Supermultiperiod A3B5 Structures with Quantum Wells Grown by Molecular-Beam Epitaxy.

Author

Goray, L. I., Pirogov, E. V., Sobolev, M. S., Polyakov, N. K., Dashkov, A. S., Svechnikov, M. V., and Bouravleuv, A. D.

Subjects
X-ray reflectometry, SYNCHROTRON radiation sources, EPITAXY, DOPED semiconductor superlattices, QUANTUM wells, MOLECULAR beam epitaxy, STANDARD deviations
Abstract

Elastically strained supermultiperiod (100–1000 periods) AlGaAs/GaAs superlattices with different doping levels and slightly differing period thicknesses have been investigated. The proposed technique of characterization consisting of combined application of deep X-ray reflectometry based on a rigorous calculation method, as well as the well-known method of high-resolution X-ray reflectometry, has made it possible to investigate 100-period structures with 2-nm-wide Al0.3Ga0.7As barriers and 10-nm-wide GaAs wells and determine with a high accuracy the layer thicknesses and spread of interfaces. This achievement can be considered as a first step in further analysis of thick structures using bright synchrotron radiation source. The difference between the expected and obtained by the proposed method layer thicknesses is several percent, including that for samples with a high doping level (up to 1018 cm–3). All supermultiperiod structures are characterized by sharp interfaces with a standard deviation of about 0.1 nm. Based on the obtained data on the thicknesses, one can accurately determine the layer compositions using high-resolution X-ray diffraction. [ABSTRACT FROM AUTHOR]

Published
2020
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