Secondary electron yield measurements of carbon covered multilayer optics

Chen, Juequan; Louis, Eric; Verhoeven, J.; Harmsen, Rob; Lee, Chris; Lubomska, Monika; Kampen, M. van; Schaik, Willem van; Bijkerk, Frederik

doi:10.1016/j.apsusc.2010.06.075

Cited by 21 publications

(11 citation statements)

References 24 publications

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“…This signifies accumulation of carbon atoms on the target surface 35 as the carbon layer causes a reduction of the SE yield by attenuating the migration of SEs toward the target surface, and thus the escape probability of SEs. 36 This is in accordance with our EUVR data [see Fig. 5(a)].…”

Section: Euv Photoelectron Spectroscopysupporting

confidence: 93%

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Time dependent changes in extreme ultraviolet reflectivity of Ru mirrors from electron-induced surface chemistry

Kanjilal

Catalfano

Harilal

et al. 2012

Journal of Applied Physics

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Time dependent changes in 13.5 nm extreme ultraviolet (EUV) reflectivity of Ru mirrors due to variations in surface composition were investigated. The surface properties of Ru films were analyzed in situ by means of X-ray photoelectron spectroscopy (XPS), and further verified by Auger electron spectroscopy (AES). Moreover, the impact on EUV reflectivity (EUVR) with time was examined in situ via continuous and/or discrete EUV exposures. The rapid decrease in EUVR was observed in the presence of photoelectrons (PEs) from Ru mirror of the EUV setup, whereas no significant variation was recorded by screening out additional PEs. Detailed XPS and AES analyses suggest that carbon deposition via dissociation of residual hydrocarbons plays a dominant role in the presence of additional PEs, and thus reduces the reflectivity rapidly. Using EUV photoelectron spectroscopy, systematic reduction of the secondary electron yield from the Ru mirror surface was observed in consecutive scans, and therefore supports the formation of carbonaceous Ru surface in the presence of additional PEs. V

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Section: Euv Photoelectron Spectroscopysupporting

confidence: 93%

“…5(a)]. In addition, a slight fluctuation of the maximum peak position can be attributed to non-uniformity 36 and anisotropy 6 in the deposited carbon layer.…”

Section: Euv Photoelectron Spectroscopymentioning

confidence: 99%

Time dependent changes in extreme ultraviolet reflectivity of Ru mirrors from electron-induced surface chemistry

Kanjilal

Catalfano

Harilal

et al. 2012

Journal of Applied Physics

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“…7 However, we observed an increase in d with EUV exposure. 21 Independent of primary electron energy 30 and 92 eV photons, 5 as d of a typical MLM was found to decrease drastically with increasing carbon coverage, the observed increase in SEs under EUV exposure only 21 indicates the dominant role of water molecules on Ru for supplying free O atoms, 11 which in turn take part in cleaning a fraction of C. A recent observation of a gradual decrease in SEs with eEUV radiation, 17 however, can change the scenario, indicating more hydrocarbons to dissociate than water molecules in the presence of additional PEs that take control of C growth and O desorption ( Fig. 1) and so the EUVR (Fig.…”

Section: Resultsmentioning

confidence: 99%

Tracking electron-induced carbon contamination and cleaning of Ru surfaces by Auger electron spectroscopy

Kanjilal¹,

Catalfano²,

Harilal³

et al. 2012

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

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Extreme ultraviolet (EUV) radiation induced growth of carbon and oxygen desorption were investigated on a Ru surface by Auger electron spectroscopy (AES) in the presence and absence of additional photoelectrons (PEs) from a focusing Ru mirror. A decrease in EUV reflectivity with carbon growth in the presence of additional PEs has been observed. Conversely, a carbonaceous Ru surface was cleaned in sequential AES, and discussed in terms of secondary electron assisted dissociation of residual hydrocarbons and water molecules, followed by a chemical reaction between adsorbed carbon and oxygen atoms. V

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“…An extremely vast range of research spanning from detectors, photon or electron-multipliers, high power microwave tubes, systems for satellite applications [1], radio-frequency cavities [2], to optics for extreme ultraviolet (EUV) lithography [3], bases some of their essential functionalities on the number of electrons produced by a surface when hit by other electrons. This quantity, called secondary electron yield (SEY), is defined as the ratio of the number of emitted electrons (also called secondary electrons) to the number of incident electrons (also called primary electrons) [4], and is commonly denoted by δ.…”

Section: Introductionmentioning

confidence: 99%

Detailed investigation of the low energy secondary electron yield of technical Cu and its relevance for the LHC

Cimino

Gonzalez

Iadarola

et al. 2015

Phys. Rev. ST Accel. Beams

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The detailed study of the low energy secondary electron yield (LE-SEY) of technical Cu for low electron energies (from 0 to 20 eV) is very important for electron cloud build up in high intensity accelerators and in many other fields of research. Different devices base their functionalities on the number of electrons produced by a surface when hit by other electrons, namely its SEY, and, in most cases, on its very low energy behavior. However, LE-SEY has been rarely addressed due to the intrinsic experimental complexity to control very low energy electrons. Furthermore, several results published in the past have been recently questioned, allegedly suffering from experimental systematics. Here, we critically review the experimental method used to study LE-SEY and precisely define the energy region in which the experimental data can be considered valid. By analyzing the significantly different behavior of LE-SEY in clean polycrystalline Cu (going toward zero at zero impinging energies) and in its as received technical counterpart (maintaining a significant value in the entire region), we solve most, if not all, of the apparent controversy present in the literature, producing important inputs for better understanding the device performances related to their LE-SEY. Simulations are then performed to address the impact of such results on electron cloud predictions in the LH

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Secondary electron yield measurements of carbon covered multilayer optics

Cited by 21 publications

References 24 publications

Time dependent changes in extreme ultraviolet reflectivity of Ru mirrors from electron-induced surface chemistry

Time dependent changes in extreme ultraviolet reflectivity of Ru mirrors from electron-induced surface chemistry

Tracking electron-induced carbon contamination and cleaning of Ru surfaces by Auger electron spectroscopy

Detailed investigation of the low energy secondary electron yield of technical Cu and its relevance for the LHC

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