A study on soft x-ray spectra from pulsed 1 <i>μ</i>m Nd:YAG laser-induced ytterbium plasmas

Wu, Tao; He, Jun; Yang, Li; Lu, Peixiang

doi:10.1088/2058-6272/aba1da

Cited by 4 publications

(3 citation statements)

References 32 publications

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“…Recently, emission spectra based on Nd:YAG LPP in the 6.x nm band for lanthanide elements such as Tm [26] and Sm [27] have been investigated experimentally and theoretically. T Wu et al [28][29][30][31][32] have studied the BEUV radiation characteristics of Ho, Pb, Mo, Bi, and Yb LPPs in the range of 1-8 nm. A V Wezyk et al [33] have studied the EUV emission spectra of laser-generated plasma of Gd and Tb targets at wavelength of 6.x nm.…”

Section: Introductionmentioning

confidence: 99%

Study of the 6.x nm short wavelength radiation spectra of laser-produced erbium plasmas for BEUV lithography

Wang

Chen

et al. 2023

Plasma Sci. Technol.

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Beyond extreme ultraviolet (BEUV) radiation with a wavelength of 6.x nm for lithography is responsible for reducing source wavelength to enable continued miniaturization of semiconductor devices. In this work, the required BEUV light at 6.x nm wavelength is generated in a dense and hot Nd:YAG laser produced erbium (Er) plasmas. The spectral contributions from the 4p–4d and 4d–4f transitions of singly-excited, doubly-excited and triply-excited states of Er XXIV-Er XXXII in the BEUV band were calculated using Cowan and the Flexible Atomic Code. It is also found that the radiative transitions between multiply-excited states dominate the narrow wavelength window around 6.x nm. Under the assumption of collisional-radiative equilibrium (CRE) of the laser produced Er plasmas, the relative ion abundance in the experiment was inferred. Using the Boltzmann quantum states energy level distribution and Gram-Charlier fitting function of unresolved transition arrays (UTA), the synthetic spectrum around 6.x nm was finally obtained and compared with experimental spectrum. The spatio-temporal distributions of electron density and electron temperature were calculated based on radiation hydrodynamic simulation in order to identify the contribution of various ionic state on the UTAs arising from the Er plasmas near 6.x nm.

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Section: Introductionmentioning

confidence: 99%

Study of the 6.x nm short wavelength radiation spectra of laser-produced erbium plasmas for BEUV lithography

Wang

Chen

et al. 2023

Plasma Sci. Technol.

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“…material processing, medicine and industrial applications [1]. LIP is one of the best sources of electrons, ions and x-rays [2]. High-energy ions can be used effectively in material processing [3], ion implantation [4], surface modification [5] and thin-film deposition [6].…”

Section: Introductionmentioning

confidence: 99%

Energy and flux measurements of laser-induced silver plasma ions by using Faraday cup

Bhatti¹,

Bashir²,

Hayat³

et al. 2021

Plasma Sci. Technol.

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Silver (Ag) plasma has been generated by employing Nd:YAG laser (532 nm, 6 ns) laser irradiation. The energy and flux of ions have been evaluated by using Faraday cup (FC) using time of flight (TOF) measurements. The dual peak signals of fast and slow Ag plasma ions have been identified. Both energy and flux of fast and slow ions tend to increase with increasing irradiance from 7 GW cm−2 to 17.9 GW cm−2 at all distances of FC from the target surface. Similarly a decreasing trend of energies and flux of ions has been observed with increasing distance of FC from the target. The maximum value of flux of the fast component is 21.2 × 1010 cm−2, whereas for slow ions the maximum energy and flux values are 8.8 keV, 8.2 × 1012 cm−2 respectively. For the analysis of plume expansion dynamics, the angular distribution of ion flux measurement has also been performed. The overall analysis of both spatial and angular distributions of Ag ions revealed that the maximum flux of Ag plasma ions has been observed at an optimal angle of ∼15°. In order to confirm the ion acceleration by ambipolar field, the self-generated electric field (SGEF) measurements have also been performed by electric probe; these SGEF measurements tend to increase by increasing laser irradiance. The maximum value of 232 V m−1 has been obtained at a maximum laser irradiance of 17.9 GW cm−2.

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“…Recent studies of LPPs in the EUV/SXR spectral region illustrate n = 3-n = 4 and n = 4-n = 5 transitions in addition to n = 4-n = 4 arrays, as well as individual lines and groups of lines. Wu et al [14] report spectra, between 1.0 and 8.5 nm, of ytterbium plasmas formed by pulses from a neodymium aluminium-garnet (Nd:YAG) laser operating at the fundamental wavelength of 1064 nm. Transitions from the 4p and 4d subshells in ions ranging from Yb 13+ to Yb 34+ are identified.…”

Section: Introductionmentioning

confidence: 99%

Soft x-ray spectra of cerium laser-produced plasmas

White

O'Sullivan

Dunne

2021

J. Phys. B: At. Mol. Opt. Phys.

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Spectra of laser-produced plasmas of cerium have been recorded in the 1.5 to 15.5 nm spectral region. The plasmas were formed using the frequency doubled pulsed output of a neodymium-doped yttrium aluminium garnet (Nd:YAG) laser at 532 nm. At the power densities incident on-target, ranging from 8.6×109- 2.1×1013W cm-2, Ce4+ to Ce27+ ions gave rise to emission from ∆n = 0, 1 transitions to ﬁnal states where n = 4. The spectra are dominated by an intense unresolved transition array (UTA) in the 8-10 nm region arising from n = 4 to n = 4 transitions. Two distinct components of this UTA are observed whose appearance is strongly dependent on laser power density, corresponding to transitions involving ions with open 4d and open 4f subshells, the latter at longer wavelengths. Multiple other transition arrays are identiﬁed and UTA statistics are given. The analysis was aided by atomic structure calculations and the use of a steady state collisional-radiative (CR) model.

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A study on soft x-ray spectra from pulsed 1 μm Nd:YAG laser-induced ytterbium plasmas

Cited by 4 publications

References 32 publications

Study of the 6.x nm short wavelength radiation spectra of laser-produced erbium plasmas for BEUV lithography

Study of the 6.x nm short wavelength radiation spectra of laser-produced erbium plasmas for BEUV lithography

Energy and flux measurements of laser-induced silver plasma ions by using Faraday cup

Soft x-ray spectra of cerium laser-produced plasmas

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