The mechanism of alumina formation from TMA and molecular oxygen using Catalytic-CVD with a tungsten catalyzer

Ogita, Yoh‐Ichiro; Tomita, Toshiyuki

doi:10.1016/j.tsf.2005.07.100

Cited by 11 publications

(3 citation statements)

References 8 publications

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“…Hence, the application field of the hot-wire CVD technique spreads widely. However, we have little report concerning depositions of oxide films, 11,12) because a filament will be oxidized by oxygen atoms incorporated into source materials. In this paper, we have tried to prepare TiO 2 films by applying the hot-wire CVD technique in order to clarify the potency of the technique for making oxide thin films.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Assisted Nano-crystallization in TiO₂ Thin Film Prepared by Hot-Wire Chemical Vapor Deposition

Iida

Koie

Masuda

et al. 2009

jjap

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Preparations and structural studies of TiO 2 thin films using hot-wire chemical vapor deposition (CVD) (hot-filament CVD) are reported for the first time. Titanium tetra-isopropoxide [Ti(OC 3 H 7 ) 4 ] was used as a source gas and decomposed on a heated rhenium filament. The film deposited at the filament temperature (T f ) of 1300 C shows amorphous structure with the substrate temperature (T s ) of 300 C, and X-ray diffraction (XRD) peaks originated from nano-crystalline with anatase structure appeared over T s of 400 -700 C. The optical band gap energies of the nano-crystalline TiO 2 films with anatase structure were 3:4 eV. An increase of T s from 400 to 700 C enhanced the XRD peak intensity of (112) orientation. Meanwhile, an increase of T f up to 1500 C induces nano-crystalline TiO 2 with rutile structure. Furthermore, the hydrogen dilution realizes the nano-crystallite growth of rutile structure even in the deposition at T f ¼ 1300 C. During this deposition, the actual substrate surface temperature (T suf ) was 305 C. In bulk TiO 2 materials, the anatase structure changes to the rutile structure by thermal annealing up to about 800 C. We propose for the first time that atomic hydrogen contributes to the low temperature nucleation of rutile structure in the deposition of oxide system, TiO 2 films.

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Section: Introductionmentioning

confidence: 99%

Hydrogen Assisted Nano-crystallization in TiO₂ Thin Film Prepared by Hot-Wire Chemical Vapor Deposition

Iida

Koie

Masuda

et al. 2009

jjap

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“…This is because tungsten, one of the most widely used catalyzer materials, is easily oxidized and the vapor pressure of tungsten oxide is much higher than that of tungsten metal. According to Ogita and his coworkers, the typical lifetime of tungsten catalyzers used in the presence of trimethyl aluminum and O 2 to deposit Al 2 O 3 is as short as 25 min [1,2]. This problem can be avoided by using Ir instead of W [3,4].…”

Section: Introductionmentioning

confidence: 99%

Catalytic CVD processes of oxidizing species and the prevention of oxidization of heated tungsten filaments by H2

et al. 2008

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The catalytic decomposition conditions of O 2 , N 2 O and NO were investigated to avoid oxidization of heated tungsten filaments. It was confirmed that no oxidization takes place in the presence of an excess amount of H 2 or NH 3 : for example, when the catalyzer temperature is 1990 K and the H 2 /O 2 flow rate ratio is more than 18. These results are consistent with the recent results that no oxidization is observed in the SiH 4 / NH 3 /H 2 /O 2 /He system to deposit SiO x N y films as long as the O 2 flow rate is low. In addition, it was revealed that in this SiH 4 /NH 3 /H 2 /O 2 /He system, O 2 is not only decomposed on the catalyzer surfaces but also is consumed in homogeneous and/or heterogeneous reactions. One of the consumption paths in the gas phase should be the reaction with SiH 3 to produce SiO.

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“…10) Several kinds of oxide films such as SiO 2 and Al 2 O 3 have been formed using Ir catalyzers, 11,12) similarly to those formed employing W catalyzers. 13,14) Although Ir is a promising catalytic metal, Ir is a typical rare metal and costly for practical use.…”

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confidence: 99%

Low-temperature silicon oxidation using oxidizing radicals produced by catalytic decomposition of H₂O/H₂ on heated tungsten wire

Katamune

Negi

Tahara

et al. 2018

Jpn. J. Appl. Phys.

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The surface oxidization of Si(100) substrates by oxidizing species generated by the catalytic decomposition of H2O precursors on a heated tungsten wire in a mixed H2O/H2 gas atmosphere was investigated. The formation of Si oxide layers was realized at stage temperatures of not more than 350 °C. From X-ray photoelectron spectroscopy measurements, their thicknesses were estimated to be 1–2 nm. In the tungsten wire temperature range from 1000 to 1450 °C, the oxidation of the wire was suppressed at H2O/H2 ratios of not more than 0.2%, which hardly caused tungsten contamination of the oxide layers.

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The mechanism of alumina formation from TMA and molecular oxygen using Catalytic-CVD with a tungsten catalyzer

Cited by 11 publications

References 8 publications

Hydrogen Assisted Nano-crystallization in TiO₂ Thin Film Prepared by Hot-Wire Chemical Vapor Deposition

Hydrogen Assisted Nano-crystallization in TiO₂ Thin Film Prepared by Hot-Wire Chemical Vapor Deposition

Catalytic CVD processes of oxidizing species and the prevention of oxidization of heated tungsten filaments by H2

Low-temperature silicon oxidation using oxidizing radicals produced by catalytic decomposition of H₂O/H₂ on heated tungsten wire

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The mechanism of alumina formation from TMA and molecular oxygen using Catalytic-CVD with a tungsten catalyzer

Cited by 11 publications

References 8 publications

Hydrogen Assisted Nano-crystallization in TiO2 Thin Film Prepared by Hot-Wire Chemical Vapor Deposition

Hydrogen Assisted Nano-crystallization in TiO2 Thin Film Prepared by Hot-Wire Chemical Vapor Deposition

Catalytic CVD processes of oxidizing species and the prevention of oxidization of heated tungsten filaments by H2

Low-temperature silicon oxidation using oxidizing radicals produced by catalytic decomposition of H2O/H2 on heated tungsten wire

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Product

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Hydrogen Assisted Nano-crystallization in TiO₂ Thin Film Prepared by Hot-Wire Chemical Vapor Deposition

Hydrogen Assisted Nano-crystallization in TiO₂ Thin Film Prepared by Hot-Wire Chemical Vapor Deposition

Low-temperature silicon oxidation using oxidizing radicals produced by catalytic decomposition of H₂O/H₂ on heated tungsten wire