Mass spectrometric study of gas-phase chemistry in the hot-wire CVD processes of SiH4/NH3 mixtures

Shi, Yujun; Eustergerling, Brett; Li, X.M.

doi:10.1016/j.tsf.2007.06.029

Cited by 11 publications

(17 citation statements)

References 15 publications

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“…This suggests that the majority of the intensity at m/z = 92 in Figures 1d) -1f) must originate from a new species, which was proposed to be tetraaminosilane, Si(NH 2 ) 4 , in our previous work. 15 The peak at m/z = 76 was not consistently observed in our previous work due to the weak nature of this signal from using the dual SPI/LIEI source. When using the pure SPI source in this work, the signal intensity for the peaks at m/z = 92 and 76 is enhanced.…”

Section: 23mentioning

confidence: 63%

“…Our previous experiments on detecting the reaction products from using NH 3 -SiH 4 mixtures in a HWCVD reactor employed a time-of-flight mass spectrometer with an ionization source of coexisting laser induced electron impact ionization (LIEI) and a 118 nm vacuum ultraviolet (VUV) laser single-photon ionization (SPI), 14,15 , the pure VUV SPI source coupled with TOF MS is employed in this work for the examination of aminosilane and disilane/trisilane formation.…”

Section: Methodsmentioning

confidence: 99%

“…Our examination of the reaction chemistry of NH 3 in the HWCVD process has found that the major gas-phase products correspond to hydrogen and nitrogen. 14,15 The deposition chemistry of ammonia in the HWCVD process has been well characterized by Umemoto et al 29 They have identified H and NH 2 radicals as the primary decomposition products of NH 3 on the hot W filaments. Signals from H 2 and N 2 were also detected using mass spectrometry.…”

Section: 23mentioning

confidence: 99%

“…However, very little is known about the formation of compounds containing direct silicon-nitrogen bond in the gas-phase in the HWCVD processes using NH 3 -SiH 4 mixtures. In our study of examining the gas-phase chemical products of an NH 3 -SiH 4 mixture with an NH 3 to SiH 4 partial pressure ratio of 100 : 1 15 , the notable different intensity ratio of the peak at m/z = 92 to that at m/z = 62 from that assumed by pure SiH 4 samples and the observation of a peak at m/z = 76 has led us to conclude that tetraaminosilane, Si(NH 2 ) 4 , is formed in the process with this mixture. Aminosilane species have been proposed in previous studies to be very important filmgrowth precursors in PECVD 4 and photo-assisted CVD using excimer laser radiation at 193 nm 7 .…”

Section: Introductionmentioning

confidence: 99%

“…Though plasma CVD chemistry with NH 3 -SiH 4 mixtures has been well studied, it is unclear if the same chemistry and mechanisms are taking place in the HWCVD process. Aminosilanes have been identified only recently in HWCVD, 15 and no detailed investigation into their formation mechanism has been presented. In this work, we present a more thorough discussion of the evidence in favor of the formation of aminosilane species in the HWCVD process using various SiH 4 and NH 3 gas mixtures with different partial pressure ratios to determine the experimental condition that favor their production.…”

Section: Introductionmentioning

confidence: 99%

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Formation of aminosilanes in the hot-wire chemical vapor deposition process using SiH4-NH3 gas mixtures

Eustergerling¹,

Shi²

2008

Arkivoc

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Vacuum ultraviolet laser single photon-ionization coupled with time-of-flight mass spectrometry has been used to detect the gas-phase reaction products from the HWCVD reactor with SiH 4 -NH 3 mixtures with various partial pressure ratios ranging from 1: 1 to 200 : 1 for NH 3 : SiH 4 . The identity of the products depends strongly on the relative amounts of SiH 4 and NH 3 in the mixture. Low NH 3 content favors the production of disilane and trisilane. When the NH 3 content is high, the formation of aminosilanes becomes the primary pathway. The production of sufficient amount of NH 2 (or ND 2 ) radicals is found to play a key role in the competition between the two pathways. The formation of aminosilanes when using mixtures with an ammonia to silane pressure ratio greater than 49 : 1 is confirmed through the use of the isotopomer ND 3 in place of NH 3 in the gas mixtures. A stepwise amination reaction scheme, initiated by the reaction between the SiH 3 and NH 2 radicals, is responsible for the formation of aminosilanes. The effect of filament temperature on the formation of aminosilanes and di-/trisilane has also been investigated.

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Section: 23mentioning

confidence: 63%

Section: Methodsmentioning

confidence: 99%

Section: 23mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Formation of aminosilanes in the hot-wire chemical vapor deposition process using SiH4-NH3 gas mixtures

Eustergerling¹,

Shi²

2008

Arkivoc

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Hot‐Wire Assisted ALD: A Study Powered by In Situ Spectroscopic Ellipsometry

Kovalgin

Yang

Banerjee

et al. 2017

Adv Materials Inter

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Hot‐wire assisted atomic layer deposition (HWALD) is a novel energy‐enhancement technique. HWALD enables formation of reactive species (radicals) at low substrate temperatures, without the generation of energetic ions and UV photons as by plasma. This approach employs a hot wire (tungsten filament) that is heated up to a temperature in the range of 1300–2000 °C to dissociate precursor molecules. HWALD has the potential to overcome certain limitations of plasma‐assisted processes. This work investigates the ability of a heated tungsten filament to catalytically crack molecular hydrogen or ammonia into atomic hydrogen and nitrogen‐containing radicals. The generation of these radicals and their successful delivery to the wafer (substrate) surface are experimentally confirmed by dedicated tellurium‐etching and silicon‐nitridation experiments. It further reports on deposition of low‐resistivity oxygen‐free tungsten films by using HWALD, as well as on the effect of hot‐wire‐generated nitrogen radicals and atomic hydrogen in deposition of aluminum nitride and boron nitride films. In parallel, this work provides important illustrative examples of using in situ real‐time monitoring of deposition and etching processes, together with extracting a variety of film properties, by spectroscopic ellipsometry technique.

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Application of laser induced electron impact ionization to the deposition chemistry in the hot-wire chemical vapor deposition process with SiH₄-NH₃ gas mixtures

Eustergerling

Hedén

Shi

2007

J. Am. Soc. Mass Spectrom.

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The application of a laser-induced electron impact (LIEI) ionization source in studying the gas-phase chemistry of the SiH(4)/NH(3) hot-wire chemical vapor deposition (HWCVD) system has been investigated. The LIEI source is achieved by directing an unfocused laser beam containing both 118 nm (10.5 eV) vacuum ultraviolet (VUV) and 355 nm UV radiations to the repeller plate in a time-of-flight mass spectrometer. Comparison of the LIEI source with the conventional 118 nm VUV single-photon ionization (SPI) method has demonstrated that the intensities of the chemical species with ionization potentials (IP) above 10.5 eV, e.g., H(2), N(2) and He, have been significantly enhanced with the incorporation of the LIEI source. It is found that the SPI source due to the 118 nm VUV light coexists in the LIEI source. This allows simultaneous observations of parent ions with enhanced intensity from VUV SPI and their "fingerprint" fragmentation ions from LIEI. It is, therefore, an effective tool to diagnose the gas-phase chemical species involved with both NH(3) and SiH(4) in the HWCVD reactor. In using the LIEI source to SiH(4), NH(3) and their mixtures, it has been shown that the NH(3) decomposition is suppressed with the addition of SiH(4) molecules. Examination of the NH(3) decomposition percentage and the time to reach the N(2) and H(2) steady-state intensities for various NH(3)/SiH(4) mixtures suggests that the extent of the suppression is enhanced with more SiH(4) content in the mixture. With increasing filament temperatures, the negative effect of SiH(4) becomes less important.

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Mass spectrometric study of gas-phase chemistry in the hot-wire CVD processes of SiH4/NH3 mixtures

Cited by 11 publications

References 15 publications

Formation of aminosilanes in the hot-wire chemical vapor deposition process using SiH4-NH3 gas mixtures

Formation of aminosilanes in the hot-wire chemical vapor deposition process using SiH4-NH3 gas mixtures

Hot‐Wire Assisted ALD: A Study Powered by In Situ Spectroscopic Ellipsometry

Application of laser induced electron impact ionization to the deposition chemistry in the hot-wire chemical vapor deposition process with SiH₄-NH₃ gas mixtures

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Mass spectrometric study of gas-phase chemistry in the hot-wire CVD processes of SiH4/NH3 mixtures

Cited by 11 publications

References 15 publications

Formation of aminosilanes in the hot-wire chemical vapor deposition process using SiH4-NH3 gas mixtures

Formation of aminosilanes in the hot-wire chemical vapor deposition process using SiH4-NH3 gas mixtures

Hot‐Wire Assisted ALD: A Study Powered by In Situ Spectroscopic Ellipsometry

Application of laser induced electron impact ionization to the deposition chemistry in the hot-wire chemical vapor deposition process with SiH4-NH3 gas mixtures

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Application of laser induced electron impact ionization to the deposition chemistry in the hot-wire chemical vapor deposition process with SiH₄-NH₃ gas mixtures