Direct photolysis of tetrafluoroethylene at 1849 Å

Dacey, J. R.; Littler, John

doi:10.1139/v69-644

Cited by 12 publications

(5 citation statements)

References 5 publications

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“…Photolysis of C2F4 always produced C2F2 and polymer as well. 13 The consistency of the results deduced by mass spectrometric examination of the gases in the discharge tube, and the results of photolysis lead to the conclusion that the neutral chemistry in the discharge tube is dominated by a few simple reactions:…”

Section: Resultsmentioning

confidence: 88%

Ionic and neutral species detected by mass spectrometry in a radio-frequency discharge of tetrafluoroethylene

Vasile¹,

Smolinsky²

1977

J. Phys. Chem.

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Publication costs assisted by Bell LaboratoriesThe chemistry of the radio-frequency discharge of C2F4 is dominated by the production of neutral gas phase species and polymeric deposits on the electrodes and walls of the discharge vessel. Ionic species observed in the discharge are characteristic of electron impact ionization of C2F4 and the neutral products: C2F6, C3F6, C3F8, and C4F8. In contrast to discharges of hydrocarbons, ion-molecule reactions are not a dominant feature of the C2F4 discharge. Appearance potential measurements gave direct evidence for the effusion of CF2 radicals from the discharge, but not for CF or CF3 radicals. At pressures above 0.1 Torr, small fragments of the polymer were sputtered and showed in the discharge as C+, CF+, and CF2+ ions. Sputtering of the discharge-produced polymer with xenon gave the ions C+, CF+, CF2+, and CF3+ by charge exchange, with no detectable buildup of the corresponding neutral fragments.

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Section: Resultsmentioning

confidence: 88%

Ionic and neutral species detected by mass spectrometry in a radio-frequency discharge of tetrafluoroethylene

Vasile¹,

Smolinsky²

1977

J. Phys. Chem.

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“…7. Experimentally, the photo-decomposition reaction from C 2 F 4 to 2CF 2 was found in the mercury sensitized decomposition at 253.7 nm (4.89 eV) line, 36) and the direct photo-dissociation to 3 B 1u was reported in ArF laser (193 nm) irradiation by Minton et al 37) It was not reported experimentally whether the 1 B 2g and 3 B 2g excited states are dissociative or not. The calculated results show these excited states are dissociative, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Dissociation Channels of c-C₄F₈ to CF₂ Radical in Reactive Plasma

Hayashi

Ishikawa

Sekine

et al. 2011

Jpn. J. Appl. Phys.

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It has been generally assumed that octafluorocyclobutane (c-C4F8) is mainly decomposed to CF2 via C2F4 in etching process plasma. However, the detailed mechanism for the dissociations is yet ambiguous. In this paper we have calculated the probable dissociation pathways by using ab initio molecular orbital method. The results show that c-C4F8 is dissociated via the first triplet excited state T1(3A2), the fourth triplet excited state T4(32E) and the fourth singlet excited state S4(12E). One of the degenerate excited states of T4 and S4 is constituted by antibonding combination of two π bonding orbital of C2F4. T1 state is constituted by antibonding combination of b1u antibonding σ orbital of C2F4. Therefore, in the case of the dissociation via S4 and T4 excited states c-C4F8 may dissociate to two C2F4, and in the case of the dissociation via T1 excited state c-C4F8 may dissociate to four CF2 radicals. It is also found that C3F5 + ion observed as the main peak in c-C4F8 process plasma is produced by electron collision with the slightly larger energy than the ionization threshold value. The main dissociation path of C2F4 is a vertical electron attachment. However, it is also found that dissociation pathways via 1B2g, 3B1u, and 3B2g excited states are very important and should not be ignored.

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“…17 The quantum yield of all products depended on the T F E pressure, with the polymeric material showing a relative decrease in yield as the pressure was increased to about 1 torr.…”

Section: Ooocmentioning

confidence: 98%

“…It may be noted that Uacey and Littler have recently indicated that, in addition to c$6, CZFZ, c-CZS, C-CaF6, C3F6, and C3Fs, some "high molecular weight product" is produced during photolysis of CzF4 at 1849 A. 17 The quantum yield of all products depended on the T F E pressure, with the polymeric material showing a relative decrease in yield as the pressure was increased to about 1 torr.…”

Section: Ooocmentioning

confidence: 99%