Chemical interaction of NF3 ion beams and plasmas with Si (Part I): X-ray photoelectron spectroscopy studies

Little, Thomas W.; Ohuchi, Fumio S.

doi:10.1016/s0039-6028(99)01061-4

Cited by 17 publications

(8 citation statements)

References 36 publications

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“…The atomic fractions of N and F are stated in Figure , showing that the N fraction of all samples was significantly less than the 25% expected if all NF 3 atoms remained on the surface. An F 1s spectrum measured with lower pass energy (not shown) yields that the peak maximum is located at 687.2 eV, as expected for a mixture of F–Si and F bound to a more electronegative element like N. , We note that our data agree with a previous study that showed that chemisorption of NF 3 onto Si(100) results in the formation of Si–F and Si–N bonds with substoichiometric N . The escape of nitrogen atoms is possible in the form of NF x and N 2 gas.…”

Section: Resultssupporting

confidence: 90%

“…The RPS-induced Si 2p spectral intensity thus likely stems from fluorinated and oxidized Si atoms. Possibly, a part of the surface exhibits Si-O-F groups as has been proposed for NF3 exposure in the presence of residual oxygen 33,36 .…”

Section: Nf3 Treatment Of H-si(100)mentioning

confidence: 92%

“…For the RPS-treated H−Si(100) we also find evidence of a fluorine-rich surface. This time the nitrogen fraction is even smaller, but the O content is now more than 50% of that of F 33,36 We can use the O 1s and F 1s intensity trends observed when going from the fresh to the N 2 -aged PECVD and RPS samples to deduce the origin of the valence band features. This corroborates our assessment that the peak at 10 eV and the states below 4 eV stem from F-derived states, while the features in between originate predominately from O-derived states.…”

Section: Acceptor Molecules On H−si(111)mentioning

confidence: 99%

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Energy-Level Alignment Tuning at Tetracene/c-Si Interfaces

et al. 2020

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The rational combination of tetracene (Tc) with crystalline silicon (c-Si) could greatly enhance c-Si solar cell efficiencies via singlet fission. The Tc/c-Si energy-level alignment (ELA) is thought to be central to controlling the required interface transfer processes. We modified hydrogen-terminated c-Si (H-Si) with 2,2′-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (F6TCNNQ), C60, or NF3 and probed the effect on the c-Si surface chemistry, the Tc/c-Si ELA, the Tc morphology, and solar cell characteristics using ultraviolet and X-ray photoelectron spectroscopy, atomic force microscopy, X-ray diffraction, photoluminescence transients, device measurements, and transfer matrix-optical modelling.Sub-monolayer interlayers of F6TCNNQ shifted the Tc/H-Si(111) ELA by up to 0.55 eV. C60 showed no notable effect on the ELA and proved detrimental for the Tc film morphology and solar cell performance. Neither F6TCNNQ nor C60 improved the Tc-related photocurrent significantly.NF3 CVD substituted the H-termination of H-Si(100) with more electronegative species and resulted in work functions as high as 6 eV. This changed the Tc/H-Si(100) ELA by up to 0.45 eV. NF3 plasma from a remote source caused pronounced c-Si oxidation and a diminished c-Si photoluminescence lifetime, which was not observed for NF3 plasma created in close proximity to the c-Si surface or neutral NF3. We discuss possible reasons for why the improved ELA does not lead to an improved singlet fission harvest.

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Section: Resultssupporting

confidence: 90%

Section: Nf3 Treatment Of H-si(100)mentioning

confidence: 92%

Section: Acceptor Molecules On H−si(111)mentioning

confidence: 99%

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Energy-Level Alignment Tuning at Tetracene/c-Si Interfaces

et al. 2020

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“…Si-F species typically yield F(1s) binding energies of 685.6-686.4 eV. [10][11][12][13][14] Therefore, we attribute the 686.5 eV peak to Si-F species formed by dissociative adsorption of BF 3 . The dissociation of BF 3 would be expected to produce species such as Si-BF 2 and (Si) 2 -BF.…”

mentioning

confidence: 99%

Formation of a Surface-Mediated Donor−Acceptor Complex: Coadsorption of Trimethylamine and Boron Trifluoride on the Silicon (001) Surface

Cao

Hamers

2002

J. Phys. Chem. B

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The interaction of trimethylamine and boron trifluoride on the Si(001) surface has been investigated using X-ray photoelectron (XP) spectroscopy. XP spectra show the TMA forms a dative bond with the clean Si(001) surface, while on the clean surface BF 3 bonds dissociatively, yielding Si-BF 2 and Si-F species. If the surface is first "saturated" with TMA, however, BF 3 will continue to adsorb, giving rise to new F(1s) XP peaks.Based on an analysis of the energies and thermal behavior of these peaks, we propose that the adsorption of TMA and BF 3 on the Si(001) surface leads to the formation of a novel surface-mediated donor-acceptor complex of the structure TMA-Si-Si-BF 3 .

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“…The interest in this chemistry, that started essentially for fundamental reasons [11,12], has become progressively related to the above-mentioned industrial use of NF 3 . In fact, during the etching and cleaning processes, the dissociation of pure or diluted (for example, with helium, argon, or oxygen) NF 3 generates the chemically active fluorine atoms as well as ionic species such as NF x + (x = 1-3), N 2 F + , and NO x + (x = 1, 2) [25] whose active role is substantiated by experimental [26][27][28] and theoretical evidence [29,30]. A detailed knowledge of the ion chemistry of NF 3 /O 2 and NF 3 /N 2 gaseous mixtures is also of interest for the proposed use of O 2 -and N 2 -based plasmas [31,32] to reduce the atmospheric emissions of NF 3 .…”

Section: Introductionmentioning

confidence: 99%