Theoretical analysis for thermal chemical vapor deposition from Tetraethoxysilane using a semi-empirical molecular orbital method

Mitsuhito Hirota, Nagahiro Saito, Takahiro Ishizaki, Akio Fuwa

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In order to elucidate the reaction mechanism for the Tetraethoxysilane (TEOS) thermal decomposition at atmospheric pressure, its pertinent elemental reactions involving the SiO(OC2H5)2 reaction intermediate were first proposed. For respective species formed in these elemental reactions, the total energy and the electronic state were calculated using a semi-empirical molecular method. The adsorption process which involves adsorbent species formation and surface reaction mechanism were then analyzed from the standpoint of molecular orbital formation and charge transfer mechanism, and the results are summarized as follows: (1) A reaction intermediate, SiO(OC2H5)2(1A1), is probably formed through the following β-elimination reaction route: Si(OC2H5)4(1A1)→SiO(OC2H5) 2(1A1)+C2H4(1A1)+C2H5OH (1A1). (2) The adsorption of SiO(OC2H5)2(1A1) on SiO2 occurs with charge transfer from the dangling bond of silicon atom at an active site of the SiO2 surface to the π*-LUMO unoccupied orbital of SiO(OC2H5)2(1A1). (3) The sequence of surface reactions is considered as follows: (1) First, a dissociation reaction of C2H5(2A′) takes place, whereby producing a double bond between silicon atom and oxygen atom of the intermediate, since they possess unpaired electrons. (2) Si-O bond is successively formed following the mechanism similar to the one operating in the adsorption of SiO(OC2H5)2(1A1) on SiO2. (3) Electronic state of the reactant finally formed is in the 1A1 state, which has a σ-orbital to be fully occupied with electrons.

Original languageEnglish
Pages (from-to)931-937
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume63
Issue number7
Publication statusPublished - 1999
Externally publishedYes

Fingerprint

Molecular orbitals
Chemical vapor deposition
Reaction intermediates
molecular orbitals
Surface reactions
Electronic states
vapor deposition
Silicon
Adsorption
Atoms
Charge transfer
Polymers
Dangling bonds
reaction intermediates
Electrons
Adsorbents
surface reactions
Atmospheric pressure
adsorption
Pyrolysis

ASJC Scopus subject areas

  • Metals and Alloys

Cite this

@article{7a2f0bad0a194be19d0a3c9a9a718b28,
title = "Theoretical analysis for thermal chemical vapor deposition from Tetraethoxysilane using a semi-empirical molecular orbital method",
abstract = "In order to elucidate the reaction mechanism for the Tetraethoxysilane (TEOS) thermal decomposition at atmospheric pressure, its pertinent elemental reactions involving the SiO(OC2H5)2 reaction intermediate were first proposed. For respective species formed in these elemental reactions, the total energy and the electronic state were calculated using a semi-empirical molecular method. The adsorption process which involves adsorbent species formation and surface reaction mechanism were then analyzed from the standpoint of molecular orbital formation and charge transfer mechanism, and the results are summarized as follows: (1) A reaction intermediate, SiO(OC2H5)2(1A1), is probably formed through the following β-elimination reaction route: Si(OC2H5)4(1A1)→SiO(OC2H5) 2(1A1)+C2H4(1A1)+C2H5OH (1A1). (2) The adsorption of SiO(OC2H5)2(1A1) on SiO2 occurs with charge transfer from the dangling bond of silicon atom at an active site of the SiO2 surface to the π*-LUMO unoccupied orbital of SiO(OC2H5)2(1A1). (3) The sequence of surface reactions is considered as follows: (1) First, a dissociation reaction of C2H5(2A′) takes place, whereby producing a double bond between silicon atom and oxygen atom of the intermediate, since they possess unpaired electrons. (2) Si-O bond is successively formed following the mechanism similar to the one operating in the adsorption of SiO(OC2H5)2(1A1) on SiO2. (3) Electronic state of the reactant finally formed is in the 1A1 state, which has a σ-orbital to be fully occupied with electrons.",
author = "Mitsuhito Hirota and Nagahiro Saito and Takahiro Ishizaki and Akio Fuwa",
year = "1999",
language = "English",
volume = "63",
pages = "931--937",
journal = "Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals",
issn = "0021-4876",
publisher = "Japan Institute of Metals (JIM)",
number = "7",

}

TY - JOUR

T1 - Theoretical analysis for thermal chemical vapor deposition from Tetraethoxysilane using a semi-empirical molecular orbital method

AU - Hirota, Mitsuhito

AU - Saito, Nagahiro

AU - Ishizaki, Takahiro

AU - Fuwa, Akio

PY - 1999

Y1 - 1999

N2 - In order to elucidate the reaction mechanism for the Tetraethoxysilane (TEOS) thermal decomposition at atmospheric pressure, its pertinent elemental reactions involving the SiO(OC2H5)2 reaction intermediate were first proposed. For respective species formed in these elemental reactions, the total energy and the electronic state were calculated using a semi-empirical molecular method. The adsorption process which involves adsorbent species formation and surface reaction mechanism were then analyzed from the standpoint of molecular orbital formation and charge transfer mechanism, and the results are summarized as follows: (1) A reaction intermediate, SiO(OC2H5)2(1A1), is probably formed through the following β-elimination reaction route: Si(OC2H5)4(1A1)→SiO(OC2H5) 2(1A1)+C2H4(1A1)+C2H5OH (1A1). (2) The adsorption of SiO(OC2H5)2(1A1) on SiO2 occurs with charge transfer from the dangling bond of silicon atom at an active site of the SiO2 surface to the π*-LUMO unoccupied orbital of SiO(OC2H5)2(1A1). (3) The sequence of surface reactions is considered as follows: (1) First, a dissociation reaction of C2H5(2A′) takes place, whereby producing a double bond between silicon atom and oxygen atom of the intermediate, since they possess unpaired electrons. (2) Si-O bond is successively formed following the mechanism similar to the one operating in the adsorption of SiO(OC2H5)2(1A1) on SiO2. (3) Electronic state of the reactant finally formed is in the 1A1 state, which has a σ-orbital to be fully occupied with electrons.

AB - In order to elucidate the reaction mechanism for the Tetraethoxysilane (TEOS) thermal decomposition at atmospheric pressure, its pertinent elemental reactions involving the SiO(OC2H5)2 reaction intermediate were first proposed. For respective species formed in these elemental reactions, the total energy and the electronic state were calculated using a semi-empirical molecular method. The adsorption process which involves adsorbent species formation and surface reaction mechanism were then analyzed from the standpoint of molecular orbital formation and charge transfer mechanism, and the results are summarized as follows: (1) A reaction intermediate, SiO(OC2H5)2(1A1), is probably formed through the following β-elimination reaction route: Si(OC2H5)4(1A1)→SiO(OC2H5) 2(1A1)+C2H4(1A1)+C2H5OH (1A1). (2) The adsorption of SiO(OC2H5)2(1A1) on SiO2 occurs with charge transfer from the dangling bond of silicon atom at an active site of the SiO2 surface to the π*-LUMO unoccupied orbital of SiO(OC2H5)2(1A1). (3) The sequence of surface reactions is considered as follows: (1) First, a dissociation reaction of C2H5(2A′) takes place, whereby producing a double bond between silicon atom and oxygen atom of the intermediate, since they possess unpaired electrons. (2) Si-O bond is successively formed following the mechanism similar to the one operating in the adsorption of SiO(OC2H5)2(1A1) on SiO2. (3) Electronic state of the reactant finally formed is in the 1A1 state, which has a σ-orbital to be fully occupied with electrons.

UR - http://www.scopus.com/inward/record.url?scp=0032666256&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032666256&partnerID=8YFLogxK

M3 - Article

VL - 63

SP - 931

EP - 937

JO - Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals

JF - Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals

SN - 0021-4876

IS - 7

ER -