Measurement of Absolute Densities of Si, SiH and SiH3in Electron Cyclotron Resonance SiH4/H2Plasma

Yamamoto, Yasuo; Nomura, Hideshi; Tanaka, Takao; Hiramatsu, Mineo; Hori, Masaru; Goto, Toshio

doi:10.1143/jjap.33.4320

Cited by 33 publications

(13 citation statements)

References 16 publications

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“…[6][7][8] Our current knowledge of the deposition mechanisms is inferred largely from macroscopic observations, such as the radical concentrations in the plasma during deposition 8,9 and the variation of the deposition rate with plasma conditions 10,11 obtained using various plasma and surface diagnostics. 10,[12][13][14][15][16][17][18][19] However, the reaction mechanisms between the species from the gas phase and the deposition surface are largely unascertained; even the identities of species that get incorporated into the film during growth are still under debate. 8,9,16,[20][21][22][23][24] Atomic-scale simulation can be used as a valuable tool to enhance our fundamental understanding of the plasma-surface reaction processes that occur during deposition.…”

Section: Introductionmentioning

confidence: 99%

“…23,24 In fact, the precursor itself may be a function of deposition conditions. For example, it has been shown that Si is the predominant radical in electron cyclotron resonance plasma deposition of a-Si:H. 18 A sticking coefficient of 0.05-0.3 for the SiH 3 radical on a-Si:H surfaces has been reported in the literature; 28,[30][31][32][33] the sticking coefficient expresses the total reaction probability of the radical on the deposition surface including adsorption and abstraction. Several radical-surface reaction processes a͒ Author to whom correspondence should be addressed; electronic mail: dimitris@calypso.ucsb.edu have been proposed including mechanisms for abstraction of H atoms from surface sites by impinging SiH 3 radicals, diffusion of SiH 3 radicals on the surface until they find reactive sites on the surface where they can attach to, and reaction of two SiH 3 radicals adsorbed on the surface to form Si 2 H 6 .…”

Section: Introductionmentioning

confidence: 99%

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Atomistic simulation study of the interactions of SiH3 radicals with silicon surfaces

Ramalingam

Maroudas

Aydil

1999

Journal of Applied Physics

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SiH 3 radicals created by electron impact dissociation of SiH4 in reactive gas discharges are widely believed to be the dominant precursor for plasma deposition of amorphous and nanocrystalline silicon thin films. In this article, we present a systematic computational analysis of the interactions of SiH3 radicals with a variety of crystalline and amorphous silicon surfaces through atomistic simulations. The hydrogen coverage of the surface and, hence, the availability of surface dangling bonds has the strongest influence on the radical–surface reaction mechanisms and the corresponding reaction probabilities. The SiH3 radical reacts with unit probability on the pristine Si(001)-(2×1) surface which has one dangling bond per Si atom; upon reaction, the Si atom of the radical forms strong Si–Si bonds with either one or two surface Si atoms. On the H-terminated Si(001)-(2×1) surface, the radical is much less reactive; the SiH3 radical was reflected back into the gas phase in all but two of the 16 simulations of radical impingement designed to sample the high-symmetry adsorption sites on the surface. When SiH3 reacts on the H-terminated surface, it either inserts into the Si–Si dimer bond or returns to the gas phase as SiH4 after abstracting H from the surface. The insertion into the Si–Si bond occurs through a dissociative adsorption reaction mechanism that produces two surface SiH2 species after transfer of one of the H atoms from SiH3 to one of the dimer Si atoms. The energetics and dynamics of the surface reactions are analyzed in detail. During simulations of a-Si:H film growth, adsorption onto a dangling bond, dissociative insertion, and H abstraction reactions also were observed to occur with similar energetics as the corresponding reactions on crystalline surfaces. The radical is much more mobile on surfaces of a-Si:H films than crystalline surfaces, especially when the hydrogen concentration in the amorphous film and, thus, on the surface is high.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Atomistic simulation study of the interactions of SiH3 radicals with silicon surfaces

Ramalingam

Maroudas

Aydil

1999

Journal of Applied Physics

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“…The UVAS measurement, using a silicon hollow cathode lamp as the light source, was used to measure the absolute densities of the atomic silicon in the gas phase. 19,20 The transition 3 p 2 2 P 2 Ϫ3 p4s 3 P 2 line of atomic silicon atom at 251.6 nm was used for the measurement. On the other hand, no simple measurement method has been established for obtaining the absolute density of atomic hydrogen.…”

Section: Resultsmentioning

confidence: 99%

Plasma diagnostics and low-temperature deposition of microcrystalline silicon films in ultrahigh-frequency silane plasma

Sumiya

Mizutani

Yoshida

et al. 2000

Journal of Applied Physics

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Microcrystalline silicon thin films were formed on quartz substrates by ultrahigh-frequency ͑UHF͒ plasma enhanced chemical vapor deposition from a mixture of silane (SiH 4) and hydrogen (H 2) gases at low substrate temperatures (T s). The UHF plasma was excited at a frequency of 500 MHz. The deposition rate and the crystallinity of the films were investigated as a function of H 2 dilution, total pressure, mixture ratio of SiH 4 to H 2 and T s. A crystalline fraction of 63% with a high deposition rate of 7.7 Å/s was obtained even at a T s of 100°C. At a temperature of 300°C, a crystalline fraction of approximately 86% was achieved at a deposition rate of 1.4 Å/s. Diagnostics of the UHF plasma have been carried out using a Langmuir probe, ultraviolet absorption spectroscopy, and optical emission spectroscopy. Good crystallinity was explained by the balance of the sheath voltage and atomic hydrogen densities in the UHF plasma. Namely, the UHF plasma source achieving a high density plasma with a low electron temperature enabled us to reduce the ion bombardment energy incident on the substrates while maintaining a high density of hydrogen atoms, and which improved the crystallinity at low T s .

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“…Yamamoto et al reported that the contribution of the Si atoms to thin-film formation was approximately 3.3 times as large as that of SiH 3 radicals in a ECR SiH 4 /H 2 plasma. 5) Murata et al reported that the growth of microcrystalline silicon with a preferential crystalline orientation is dependent on the balance between silicon and hydrogen atom densities in pulse-modulated ultrahigh-frequency SiH 4 /H 2 plasma. 6) Moreover, the Si atom reacts with the SiH 4 molecule at a high reaction rate and produces higher order silane-related radicals.…”

Section: Introductionmentioning

confidence: 99%

Study on the Absolute Density and Translational Temperature of Si Atoms in Very High Frequency Capacitively Coupled SiH₄ Plasma with Ar, N₂, and H₂ Dilution Gases

Ohta¹,

Hori²,

Ishida³

et al. 2004

Jpn. J. Appl. Phys.

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The absolute densities and translational temperatures of Si atoms in very high frequency capacitively coupled SiH4 plasmas diluted with Ar, N2, and H2 gases were investigated by ultraviolet absorption spectroscopy with a ring dye laser and a hollow cathode lamp. It was found that the absolute density of Si atoms was of the order of 109–1010 cm-3 and the translational temperature of Si atoms ranged from 620 to 1130 K at a total pressure of 11 Pa, a dilution gas flow rate of 100 sccm, and a SiH4 flow rate of 0–15 sccm. The absolute densities and temperatures of Si atoms in plasma at an excitation frequency of 27 MHz were larger than those at 60 MHz under the conditions at the same electron density. Si atom heating was due to the energy of Si atoms released from the electron impact dissociation of SiH x (x=1–4). The translational temperatures of Si atoms in SiH4/Ar, SiH4/N2, and SiH4/H2 plasmas were evaluated to be 970, 1030, and 1130 K, respectively, at a frequency of 27 MHz, a SiH4 flow rate of 10 sccm, and a VHF power of 1500 W. The effect of Si atoms and SiH3 radicals on film deposition was investigated for SiH4/N2 in 27 MHz and 60 MHz plasmas. From the measurement using Fourier transform infrared absorption spectroscopy, the peak of the Si–H bond decreased and that of the N–H bond increased with increasing excitation frequency. Therefore, the film deposited at 60 MHz indicated a nitride-rich composition in comparison with that at 27 MHz. The contribution ratio of Si atoms to SiH3 radicals for film deposition in 27 MHz plasma was larger than that in 60 MHz plasma. These results are very important from the viewpoint of understanding neutral radical chemistries in the plasma and their related processing.

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Measurement of Absolute Densities of Si, SiH and SiH₃in Electron Cyclotron Resonance SiH₄/H₂Plasma

Cited by 33 publications

References 16 publications

Atomistic simulation study of the interactions of SiH3 radicals with silicon surfaces

Atomistic simulation study of the interactions of SiH3 radicals with silicon surfaces

Plasma diagnostics and low-temperature deposition of microcrystalline silicon films in ultrahigh-frequency silane plasma

Study on the Absolute Density and Translational Temperature of Si Atoms in Very High Frequency Capacitively Coupled SiH₄ Plasma with Ar, N₂, and H₂ Dilution Gases

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Measurement of Absolute Densities of Si, SiH and SiH3in Electron Cyclotron Resonance SiH4/H2Plasma

Cited by 33 publications

References 16 publications

Atomistic simulation study of the interactions of SiH3 radicals with silicon surfaces

Atomistic simulation study of the interactions of SiH3 radicals with silicon surfaces

Plasma diagnostics and low-temperature deposition of microcrystalline silicon films in ultrahigh-frequency silane plasma

Study on the Absolute Density and Translational Temperature of Si Atoms in Very High Frequency Capacitively Coupled SiH4 Plasma with Ar, N2, and H2 Dilution Gases

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Product

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Measurement of Absolute Densities of Si, SiH and SiH₃in Electron Cyclotron Resonance SiH₄/H₂Plasma

Study on the Absolute Density and Translational Temperature of Si Atoms in Very High Frequency Capacitively Coupled SiH₄ Plasma with Ar, N₂, and H₂ Dilution Gases