Reaction of atomic hydrogen with hydrogenated porous silicon — detection of precursor to silane formation

Glass, John A.; Wovchko, Edward A.; Yates, John T.

doi:10.1016/0039-6028(95)01014-9

Cited by 44 publications

(39 citation statements)

References 31 publications

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“…However, the observed shifts in peak positions for the hydride stretching modes are not significant if the Si atom is bonded to one or more D atoms. 47 Thus, the dihydride stretching mode in SiHD and SiH 2 and the trihydride stretching mode in SiHD 2 , SiH 2 D, and SiH 3 appear nearly at the same frequency. In the case of higher deuterides, which are formed during D 2 plasma treatment either by exchange or by insertion, the stretching modes can shift depending on the number of H atoms bonded to the Si.…”

Section: -35āmentioning

confidence: 92%

“…The SiH x (1 рxр4) absorption band was deconvoluted into individual surface and bulk modes as labeled in the figure and listed in Table I. SiD 2 and the tri-deuteride stretching mode in SiDH 2 , SiD 2 H, and SiD 3 can appear at different wavenumbers. 47 The spectra obtained during deuteration were deconvoluted as shown in Fig. 6.…”

Section: Fig 8 Changes In the Sihmentioning

confidence: 99%

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Abstraction of atomic hydrogen by atomic deuterium from an amorphous hydrogenated silicon surface

Agarwal

Takano

Sanden

et al. 2002

The Journal of Chemical Physics

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We have studied the interactions of atomic deuterium with hydrogenated amorphous silicon (a-Si:H) surfaces using surface-sensitive infrared spectroscopy. We deconvoluted the effects of the abstraction reaction from insertion and etching reactions and determined the activation energy barrier for abstraction of H by D from a-Si:H surfaces. Both abstraction and insertion are observed in our experiments conducted over times ranging from a few seconds to hundreds of seconds and sequential insertion of D eventually results in the formation of deuterated silane and etching of the film. The abstraction rate is found to be independent of temperature with an essentially zero activation energy barrier (0.011±0.013 eV), consistent with an Eley–Rideal mechanism and in agreement with recent atomistic calculations.

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Section: -35āmentioning

confidence: 92%

Section: Fig 8 Changes In the Sihmentioning

confidence: 99%

Abstraction of atomic hydrogen by atomic deuterium from an amorphous hydrogenated silicon surface

Agarwal

Takano

Sanden

et al. 2002

The Journal of Chemical Physics

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“…4). For the H-PSi wafers before the reaction, the peak for Si-H vibrations around 2100 cm −1 was obvious, 15,16 but completely and partly disappeared after the experiment for 2.5 h in the absence and presence of light, respectively. These results indicated that both reactions should display different degradation mechanisms.…”

Section: Resultsmentioning

confidence: 97%

Degradation mechanism of hydrogen-terminated porous silicon in the presence and in the absence of light

Pei

Xiao

et al. 2015

AIP Advances

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Si is well-known semiconductor that has a fundamental bandgap energy of 1.12 eV. Its photogenerated electrons in the conduction band can react with the ubiquitous oxygen molecules to yield ⋅O2− radicals, but the photogenerated holes in the valance band can’t interact with OH− to produce ⋅OH radicals. In this paper, we study the degradation of methyl orange (MO) by hydrogen-terminated porous Si (H-PSi) in the presence and in the absence of light. The absorption spectra of the degraded MO solutions indicated that the H-PSi had superior degradation ability. In the dark, the reduction of dye occurs simply by hydrogen transfer. Under room light, however, some of the dye molecules can be reduced by hydrogen transfer first and then decomposed in the conduction and valance bands. This result should be ascribed to its wide band gap energies centered at 1.79-1.94 eV.

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“…The preferential etching of higher hydrides during exposure of a-Si:H to atomic hydrogen is fully consistent with findings in the literature. [28][29][30] HD exchange experiments on crystalline silicon have shown that the total hydrogen coverage remains close to unity (0.68ϫ10 15 cm Ϫ2 ) during atomic H or D exposure. 31 Since the a-Si:D is created by exposing an a-Si:H film to atomic deuterium, we assume that the monodeuteride at the physical surface consists of Ϸ0.7ϫ10 15 cm Ϫ2 D atoms, and that the local structure is similar to the 2ϫ1 reconstruction of Si͑100͒, since this represents the stable configuration for a hydrogen-terminated silicon surface exposed to atomic H at a substrate temperature of 230°C.…”

Section: Methodsmentioning

confidence: 95%

Direct insertion ofSiH3radicals into strained Si-Si surface bonds during plasma deposition of hydrogenated amorphous silicon films

Keudell

Abelson

1999

Phys. Rev. B

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We investigate the interaction of silyl (SiH 3 ) radicals with hydrogenated amorphous silicon (a-Si:H) films using real time in situ infrared spectroscopy in a mode that can detect as little as ϳ0.2 ML of Si-H bonds. The results are directly relevant to the growth of a-Si:H by plasma-chemical vapor deposition. In this paper, a remote silane plasma source is used to generate a pure SiH 3 beam, without any contribution of H or SiH 2 . Deuterated (a-Si:D) films are exposed to this beam and the change in the IR absorption caused by the loss of SiD groups and the creation of SiH groups is measured in real time. At the beginning of exposure to SiH 3 radicals, a hydrogen-rich layer is deposited on top of the deuterated sample, but no release of deuterium from SiD surface groups can be observed. This is a surprising result, since it has been assumed in the literature that SiH 3 radicals can easily abstract surface-bonded H atoms, and that abstraction must occur in order to create dangling bond sites on which SiH 3 radicals subsequently adsorb. Our results show that the reaction mechanism with the largest rate coefficient must be the direct insertion of SiH 3 radicals into bonding sites at the film surface, which leads to a hydrogen-rich top layer while preserving the preexisting SiD bonds. After completion of one monolayer of surface Si-H bonds, deuterium atoms from the initial surface are released simultaneously with the creation of SiH bulk groups. We propose a reaction scheme based on the direct insertion of SiH 3 radicals into strained Si-Si bonds. This scheme also predicts that the surface-bonding configurations depend on a dynamic balance between the rates of SiH 3 adsorption and thermal desorption, which is confirmed experimentally as a function of SiH 3 flux. We discuss the implications of this reaction mechanism for the growth of a-Si:H from silane discharges, and for the growth of microcrystalline Si in H 2 diluted SiH 4 discharges.

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Reaction of atomic hydrogen with hydrogenated porous silicon — detection of precursor to silane formation

Cited by 44 publications

References 31 publications

Abstraction of atomic hydrogen by atomic deuterium from an amorphous hydrogenated silicon surface

Abstraction of atomic hydrogen by atomic deuterium from an amorphous hydrogenated silicon surface

Degradation mechanism of hydrogen-terminated porous silicon in the presence and in the absence of light

Direct insertion ofSiH3radicals into strained Si-Si surface bonds during plasma deposition of hydrogenated amorphous silicon films

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