Infrared study of the adsorption, desorption, and degassing processes of trimethyl-borate on a porous high-silica glass system

Shimizu, Michie; Gesser, H. D.

doi:10.1139/v68-583

Cited by 6 publications

(7 citation statements)

References 4 publications

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“…treated in the same manner as in our previous work (9), except, in the present study, solue of them were "not acid-leachedm3 with hot 18N HNO,. After washing, some of the glasses were thermo-leached in air at 500 OC for 5-16 h until they had no infrared (i.r.)…”

Section: Adsorbentsmentioning

confidence: 69%

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An electron spin resonance study of ultraviolet photolyzed methanol adsorbed on porous high-silica glass

Shimizu¹,

Gesser²,

Fujimoto³

1969

Can. J. Chem.

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The electron spin resonance (e.s.r.) spectra of 'CH,, 'CHO, H and/or D, and possibly 'CH,OH or ' C H 2 0 D were found by the ultraviolet (u.v.1 photolysis of methanol -OH or -OD on porous highsilica glass at 77 OK. These e.s.r. spectra resemble the results of the u.v. photolysis of X-irradiated methanol indicating that some perturbation andlor sensitization occurred in the n~olecules by the glass surface. The absence of e.s.r. spectra from the same systems on the acid-leached glass, on the totally fluorinated glass, or on the totally -OH covered glass suggests that (i) the co-existence of surface contaminants, such as Al and Zr and not B, and some of surface -OH could be responsible for producing these free radicals, and (ii) the methanols adsorbed on these glass surfaces are stabilized against U.V. photolysis.

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Section: Adsorbentsmentioning

confidence: 69%

“…1365 cm-I indicating the presence of a small amount (less than 1 %) 4 of CH,-OH and trimethylborate (9). These impurities in CH3-OD could not be removed by repeating the distillation.…”

Section: Adsorbatesmentioning

confidence: 99%

An electron spin resonance study of ultraviolet photolyzed methanol adsorbed on porous high-silica glass

Shimizu¹,

Gesser²,

Fujimoto³

1969

Can. J. Chem.

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“…Upon exposures to 4.5 × 10 7 L of TMB, the appearance of a C 1s shoulder at ∼286.8 eV, corresponding to methoxy from [B(OCH 3 ) n ]* surface species, is observed (Figure 7a, red), similar to the data in Figure 2a. 50,51 An increase in the intensity of adventitious C at lower binding energies is also seen after TMB exposures. This could be due to residual carbon contamination in the ALD chamber (base pressure of ∼9 × 10 −8 Torr) where the high-flux experiments were performed.…”

Section: Resultsmentioning

confidence: 94%

“…The evolution of C 1s, O 1s, and Si 2p XPS spectra as a function of exposures at 300 K is shown in Figure 2. Here, the C 1s XPS intensity was used to determine the surface coverages instead of B 1s, since the boron intensity is 50,51 However, partial dissociation of TMB to form adsorbed methyl species at ∼285 eV cannot be ruled out. The O 1s spectrum (Figure 2b, red) shows an increase and shift of the O 1s peak from 531.8 to 532.2 eV after TMB exposures, corresponding to the adsorption of methoxy species.…”

Section: Resultsmentioning

confidence: 99%

Influence of O(³P)/O₂ Flux on the Atomic Layer Deposition of B₂O₃ Using Trimethyl Borate at Room Temperature

et al. 2020

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Oxygen plasma is crucial to many atomic layer deposition (ALD) processes, and O( 3 P) radicals play a significant role in terms of reactivity and surface modification. In situ X-ray photoelectron spectroscopy (XPS), residual gas analysis mass spectrometry (RGA-MS), and ab initio molecular dynamics (AIMD) simulations were used to study the free-radical-assisted ALD of boron oxide (B 2 O 3 ) films on Si( 100) using trimethyl borate [B(OCH 3 ) 3 ] and mixed O( 3 P)/O 2 effluents at room temperature at varying levels of O( 3 P)/O 2 flux to the surface. Under these conditions, no reaction with pure O 2 was observed. The XPS results show that at low O( 3 P)/O 2 flux, a complete removal of alkyl ligands is observed and C-free B 2 O 3 is achieved, with CO 2 and H 2 O as the main reaction products. At higher O( 3 P)/O 2 fluxes, the formation of a stable oxidized C surface layer is observed with some C incorporation into the growing B 2 O 3 film. In both flux regimes, the B 2 O 3 film thickness increased linearly with the number of cycles, consistent with an ALD process. AIMD simulations of O( 3 P) collisions with B(OCH 3 ) 3 indicate a multistep ligand removal mechanism initiated by hydrogen abstraction at a threshold O( 3 P) energy of ∼0.1 eV, consistent with RGA-MS results. In contrast, C oxidation and incorporation in the high-flux regime result from O 2 termination of the O( 3 P)-induced C radical sites. This work demonstrates that the purity of B 2 O 3 films, efficiency of ligand removal, and surface reaction products can be flux-dependent.

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“…The vibrational features indicate that methoxy groups are bonded to boron (B(OCH3)n) as well as silicon (Si(OCH3)m) on the surface. 8 This reaction diminishes the Si-OD concentration by less than 5% while consuming 95% of the (Si-O)2 rings. This suggests that (Si-O) 2 rings are -20 times more reactive than silanols with respect to SiOD / 0\ Sih Although not shown in the figure, TMB reaction at 100 mTorr for 300 sec.…”

Section: Resultsmentioning

confidence: 99%

Surface Chemistry of Boron-Doped SiO₂ CVD: Enhanced Uptake of Tetraethyl Orthosilicate by Hydroxyl Groups Bonded to Boron

Bartram¹,

Moffat²

1993

MRS Proc.

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Insight into how dopants can enhance deposition rates has been obtained by comparing the reactivities of tetraethyl orthosilicate (TEOS, Si(OCH 2 CH 3 ) 4 ) with silanol and boranol groups on SiO 2 . This comparison has direct relevance for boron-doped SiO 2 film growth from TEOS and trimethyl borate (TMB, B(OCH 3 ) 3 ) sources since boranols and silanols are expected to be present on the surface during the thermal chemical vapor deposition (CVD) process. A silica substrate having coadsorbed deuterated silanols (SiOD) and boranols (BOD) was reacted with TEOS in a cold-wall reactor in the mTorr pressure regime at 1000K. The reactions were followed with Fourier transform infrared spectroscopy. The use of deuterated hydroxyls allowed the consumption of hydroxyls by TEOS chemisorption to be distinguished from the concurrent formation of SiOH and BOH that results from TEOS decomposition at this temperature. It was found that TEOS reacts with BOD at twice the rate observed for SiOD, given equivalent concentrations of BOD and SiOD. This demonstrates that hydroxyl groups bonded to boron increase the rate of TEOS chemisorption. In contrast, additional results show that surface ethoxy groups produced by the chemisorption of TEOS decompose at a slower rate in the presence of TMB decomposition products. Possible dependencies on reactor geometries and other deposition conditions may determine which of these two competing effects will control deposition rates. This has significant implications for microelectronics fabrication since the specific dependencies would be expected to affect process reliability. In addition, this may explain (in part) why the rate enhancement effect is not always observed in boron-doped Si0 2 CVD processes. IntroductionThe addition of trimethyl borate (TMB, B(OCH 3 ) 3 ) to a thermal tetraethyl orthosilicate (TEOS, Si(OCH 2 CH 3 ) 4 ) chemical vapor deposition (CVD) process produces boron-doped oxide films. 1 Boron-doped films require a lower temperature than undoped Si0 2 films to achieve reflow in the surface planarization step during very-large-scale-integrated (VLSI) device fabrication. 1 Interestingly, the addition of dopant precursors has been observed to enhance the rate for SiO 2 deposition. 2 , 3 However, this effect is not always observed. 4 Surprisingly, there have not been any studies designed specifically to determine if there is a chemical basis for the rate enhancement effect.

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Infrared study of the adsorption, desorption, and degassing processes of trimethyl-borate on a porous high-silica glass system

Cited by 6 publications

References 4 publications

An electron spin resonance study of ultraviolet photolyzed methanol adsorbed on porous high-silica glass

An electron spin resonance study of ultraviolet photolyzed methanol adsorbed on porous high-silica glass

Influence of O(³P)/O₂ Flux on the Atomic Layer Deposition of B₂O₃ Using Trimethyl Borate at Room Temperature

Surface Chemistry of Boron-Doped SiO₂ CVD: Enhanced Uptake of Tetraethyl Orthosilicate by Hydroxyl Groups Bonded to Boron

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Infrared study of the adsorption, desorption, and degassing processes of trimethyl-borate on a porous high-silica glass system

Cited by 6 publications

References 4 publications

An electron spin resonance study of ultraviolet photolyzed methanol adsorbed on porous high-silica glass

An electron spin resonance study of ultraviolet photolyzed methanol adsorbed on porous high-silica glass

Influence of O(3P)/O2 Flux on the Atomic Layer Deposition of B2O3 Using Trimethyl Borate at Room Temperature

Surface Chemistry of Boron-Doped SiO2 CVD: Enhanced Uptake of Tetraethyl Orthosilicate by Hydroxyl Groups Bonded to Boron

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Influence of O(³P)/O₂ Flux on the Atomic Layer Deposition of B₂O₃ Using Trimethyl Borate at Room Temperature

Surface Chemistry of Boron-Doped SiO₂ CVD: Enhanced Uptake of Tetraethyl Orthosilicate by Hydroxyl Groups Bonded to Boron