Measurement and control of absolute nitrogen atom density in an electron-beam-excited plasma using vacuum ultraviolet absorption spectroscopy

Tada, Shigekazu; Takashima, Seigou; Ito, Masafumi; Hori, Masaru; Goto, Toshio; Sakamoto, Yuichi

doi:10.1063/1.1305559

Cited by 55 publications

(28 citation statements)

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“…3b), the electron density differs insignificantly. This can be attributed to the higher gas density (by an order of magnitude) in the present work, as compared with that in [14]. The character of the dependences is identical in both cases.…”

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confidence: 44%

“…Thus, the electron density in an electron-beam plasma can be changed without changing the electron energy distribution function. Figure 3 also shows the data of [14] for an electron-beam nitrogen plasma. Though the beam current in [14] is higher approximately by an order of magnitude (see Fig.…”

mentioning

confidence: 97%

“…Figure 3 also shows the data of [14] for an electron-beam nitrogen plasma. Though the beam current in [14] is higher approximately by an order of magnitude (see Fig. 3b), the electron density differs insignificantly.…”

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confidence: 97%

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Gas flow activated in an electron-beam plasma

Konstantinov

Khmel

2007

J Appl Mech Tech Phys

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Probe measurements of electron temperature and density, electron energy distribution functions, and plasma potential in a free gas jet activated in an electron-beam plasma and in a planar reactor are presented. The measurements are performed by single, double, and triple electrostatic probes in jets of helium-argon and helium-argon-monosilane gas mixtures. The latter mixture is used to deposit films of microcrystalline and epitaxial silicon. Microcrystalline silicon films of higher quality are obtained in a dense (n e ≈ 10 17 m −3 ) and cold (T e ≈ 1.0-0.5 eV) plasma with a low potential (U sp ≈ 10 V), whereas the growth of monocrystalline silicon films requires a hotter plasma (T e ≈ 3-5 eV) with a potential U sp ≈ 15 V.Key words: probe diagnostics, electron-beam plasma, chemical vapor deposition of thin silicon films.Introduction. Deposition of thin films often involves chemical vapor methods with activation of gaseous reagents in a discharge plasma or electron-beam plasma [1,2]. In particular, a silane plasma is used for silicon-film deposition [3][4][5]. The study of such a plasma is an urgent problem, and one of the most widely used diagnostic methods is the Langmuir probe [6][7][8]. Probe characteristics can yield information on the electron temperature, electron density, plasma potential, and, in the general case, the electron energy distribution function. If a single or a double probe is used, however, it is impossible to determine instantaneous values of plasma parameters (measuring and processing of the current-voltage characteristic is a rather long procedure). Such information can be obtained by a triple probe [8].It was demonstrated [9] by means of probe diagnostics that the temperature and density of secondary electrons in a nitrogen electron-beam plasma are 0.5-2.5 eV and 10 16 -10 17 m −3 , respectively. The temperature was found to decrease and the density was found to increase with increasing pressure in the electron-beam plasma. The measurements performed in an argon electron-beam plasma [10] showed that the electron temperature is approximately 1 eV, the electron density is 5 · 10 16 to 5 · 10 17 m −3 , and the plasma potential is approximately 4 V. Such a plasma produces a soft and nondestructive effect on the surface and can be used for material processing and depositing high-quality thin films [2]. Deposition of epitaxial layers requires a harder plasma, but a principally important quantity in this case is the plasma potential [11].In a reactive plasma, the probe surface is contaminated by growing films; hence, correct measurements in such a plasma are ensured by using heated probes [7]. It was found in [12] with the use of heated probes that the electron temperature and density decrease with increasing flow rate of monosilane or pressure in the discharge chamber.The present paper describes investigations performed in free jets of helium-argon and helium-argonmonosilane mixtures activated in an electron-beam plasma and in a gas flow inside a planar reactor. The goal of the present work was ...

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Gas flow activated in an electron-beam plasma

Konstantinov

Khmel

2007

J Appl Mech Tech Phys

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“…Using this system, measurements of absolute radical densities have been carried out and the behavior of these atomic radicals in various process plasmas has been clarified. 12,13,[15][16][17][18][19][20][21][22][23][24][25] However, two opposite ports are necessary to install the conventional VUVAS system with the MHCL in the plasma reactor. In order to prevent saturation of the absorption intensity, the absorption pass length has to be reduced by introducing pipes with diameters of 9 mm into the chamber.…”

Section: Development Of Atomic Radical Monitoring Probe and Its Applimentioning

confidence: 99%

Development of atomic radical monitoring probe and its application to spatial distribution measurements of H and O atomic radical densities in radical-based plasma processing

Takahashi

Takashima²,

Yamakawa³

et al. 2009

Journal of Applied Physics

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Articles you may be interested inThe multipole resonance probe: A concept for simultaneous determination of plasma density, electron temperature, and collision rate in low-pressure plasmas Appl. Phys. Lett. 93, 051502 (2008); 10.1063/1.2966351Floating probe for electron temperature and ion density measurement applicable to processing plasmas Electrostatic probe diagnostics of a planar-type radio-frequency inductively coupled oxygen plasma Atomic radicals such as hydrogen ͑H͒ and oxygen ͑O͒ play important roles in process plasmas. In a previous study, we developed a system for measuring the absolute density of H, O, nitrogen, and carbon atoms in plasmas using vacuum ultraviolet absorption spectroscopy ͑VUVAS͒ with a compact light source using an atmospheric pressure microplasma ͓microdischarge hollow cathode lamp ͑MHCL͔͒. In this study, we developed a monitoring probe for atomic radicals employing the VUVAS with the MHCL. The probe size was 2.7 mm in diameter. Using this probe, only a single port needs to be accessed for radical density measurements. We successfully measured the spatial distribution of the absolute densities of H and O atomic radicals in a radical-based plasma processing system by moving the probe along the radial direction of the chamber. This probe allows convenient analysis of atomic radical densities to be carried out for any type of process plasma at any time. We refer to this probe as a ubiquitous monitoring probe for atomic radicals.

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“…The plasma state is preserved without alteration by external radiation sources in the experiment, and the H emission has the added benefit of providing information on the electron density derived from measuring the Stark broadened 11 line profile. If a N 2 /H 2 mixture is used, the self-absorption approach can be extended 12 to simultaneously provide information on the density of N atoms by comparing the absolute intensity of H radiation to N radiation at 124.3 nm, in addition to measuring the approximate absorption characteristics of the 2s 3 transition(s) of ground state N at 119.96 nm, 120.02 nm, and 120.07 nm (collectively referred to in this paper as "120.0 nm"). It is worth noting that the self-absorption treatment could also be used to determine dissociated O density of air plasmas in the future, by using the 2s The general treatment 14 of the mechanisms leading to line broadening is well understood, and only a brief overview is presented here.…”

Section: à3mentioning

confidence: 99%