ARUPS of water adsorption on Si(100) and Si(111) surfaces

Fives, K.; McGrath, R.; Stephens, C.; McGovern, I.T.; Cimino, R.; Law, Derek; Johnson, Allen L.; Thornton, G.

doi:10.1088/0953-8984/1/sb/018

Cited by 26 publications

(5 citation statements)

References 15 publications

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“…Initial interpretations of ultraviolet photoelectron spectroscopy (UPS) on Si(100) and Si(111) suggested molecular adsorption, while electron energy loss spectroscopy (EELS) and surface IR studies showed dissociative adsorption on the basis of the Si−H and Si−O−H stretching modes. Later, photoelectron spectroscopy (PES) reinterpretation of the earlier UPS 8a data and other experiments were all consistent with dissociative adsorption. At room temperature, the sticking coefficient of water on Si(100) is near unity and constant up to saturation …”

Section: Introductionsupporting

confidence: 55%

Surface S_N2 Reaction by H₂O on Chlorinated Si(100)-2 × 1 Surface

Lee

Kim

et al. 2005

J. Phys. Chem. B

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The potential energy surfaces of one, two, and three water molecule sequential adsorptions on the symmetrically chlorinated Si(100)-2 x 1 surface were theoretically explored with SIMOMM:MP2/6-31G(d). The first water molecule adsorption to the surface dimer requires a higher reaction barrier than the subsequent second water molecule adsorption. The lone pair electrons of the incoming water molecule nucleophilically attack the surface Si atom to which the leaving Cl group is bonded, yielding an S(N)2 type transition state. At the same time, the Cl abstracts the H atom of the incoming water molecule, forming a unique four-membered ring conformation. The second water molecule adsorption to the same surface dimer requires a much lower reaction barrier, which is attributed to the surface cooperative effect by the surface hydroxyl group that can form a hydrogen bond with the incoming second water molecule. The third water molecule adsorption exhibits a higher reaction barrier than the first and the second water molecule adsorption channels but yields a thermodynamically more stable product. In general, it is expected that the surface Si-Cl bonds can be subjected to the substitution reactions by water molecules, yielding surface Si-OH bonds, which can be a good initial template for subsequent surface chemical modifications. However, oversaturations can be a competing side reaction under severe conditions, suggesting that the precise control of surface kinetic environments is necessary to tailor the final surface characteristics.

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Section: Introductionsupporting

confidence: 55%

Surface S_N2 Reaction by H₂O on Chlorinated Si(100)-2 × 1 Surface

Lee

Kim

et al. 2005

J. Phys. Chem. B

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“…4. ͑not shown͒ using the double-pass CMA taken at hϭ90 eV showed that the binding energies of the molecular orbitals for Si-OH are 6.7 eV for 1, 7.6 eV for 3, 11.8 eV for O, and 25.0 eV for 2, where 1 is the O-H nonbonding orbital, 3 is the O-H -bonding orbital, O is the Si-O -bonding orbital, and 2 mainly consists of the O 2s orbital. 12,13 According to our Mg K␣ XPS measurement, E O 1s is 532.7 eV. The value of in the present measurements was estimated as 4.5Ϯ0.3 eV.…”

Section: Photoelectron Spectroscopy and Aepico For The O-kvv Auger Elmentioning

confidence: 48%

“…[8][9][10][11] The results of vibrational spectroscopy led, however, to the reinterpretation of these and later results as indicating dissociative chemisorption. 8,[12][13][14][15][16] It is now generally accepted that H 2 O is dissociatively adsorbed on the Si͑100͒ surface to form Si-OH and Si-H surface species. 8 In a study by PSD with the surface irradiated by photons at 600 eV, i.e., in the region of O 1s excitation, the yield of desorbed H ϩ was Ϸ500 times as great as the yield of desorbed O ϩ .…”

Section: Introductionmentioning

confidence: 99%

Ion desorption induced by core-level excitation of H2O/Si(100): Evidence of desorption due to the multielectron excitation/decay

Tanaka

Mase²,

Nagaoka

et al. 2002

The Journal of Chemical Physics

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Articles you may be interested inCore-level positive-ion and negative-ion fragmentation of gaseous and condensed HCCl3 using synchrotron radiation J. Chem. Phys. 135, 044303 (2011); 10.1063/1.3615626Theoretical study of the UV-induced desorption of molecular oxygen from the reduced TiO 2 (110) surface J. Chem. Phys. 118, 5098 (2003); 10.1063/1.1545093Photon-stimulated ion desorption from mono-and multilayered silicon alkoxide on silicon by core-level excitation Study of ion desorption induced by carbon core excitation for poly-methylmethacrylate thin film using electron-ion coincidence spectroscopy This work is an investigation of the desorption by O 1s excitation of ions from Si͑100͒ reacted with water. Photoelectron, photostimulated desorption, and electron-ion coincidence spectroscopy are used to observe the process. When the incident photons have energy levels which are near the 1s threshold of O, they induce Auger decay that is accompanied by shakeup/off excitation and cascade Auger decay, and they are shown to be the main factor responsible for desorption in this case. When the photons have energy levels which are above the shakeup threshold, most of the desorption that occurs is a result of the shakeup excitation that accompanies the core excitation. In both cases, the desorption is induced by the respective multihole final states. The ion desorption yield for the two-hole final states of the normal process of Auger decay is small. The results are discussed, with the help of the Auger electron spectra, mainly in terms of the lifetime of the final state of Auger decay.

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“…The adsorption of water on silicon surfaces is important in the semiconductor industry and is extensively studied because of the relationships to fundamental phenomena in device fabrication such as growth of SiO 2 films by wet oxidation, etching, and the flatness of silicon surfaces. , In semiconductor processing, not only H 2 O but also O 2 are the most commonly used oxidants, but the presence of H 2 O rather than dry O 2 makes SiO 2 layers grow more rapidly and thus wet oxidation is preferred for SiO 2 films. The mechanisms of the adsorption of an H 2 O molecule on a silicon surface have been well studied theoretically. − Although there has been historically some controversy concerning whether H 2 O adsorbs as a molecule on Si(100)-2 × 1 surface, or dissociates to form OH and H fragments that saturate silicon dangling bonds, a consensus now exists from various observations − that water adsorbs dissociatively.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanisms of the adsorption of an H 2 O molecule on a silicon surface have been well studied theoretically. [6][7][8][9] Although there has been historically some controversy concerning whether H 2 O adsorbs as a molecule on Si(100)-2 × 1 surface, or dissociates to form OH and H fragments that saturate silicon dangling bonds, a consensus now exists from various observations [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] that water adsorbs dissociatively.…”

Section: Introductionmentioning

confidence: 99%

Possible Dissociative Adsorption of CH₃OH and CH₃NH₂ on Si(100)-2 × 1 Surface

Kato¹,

Sy²,

Xu³

et al. 2001

J. Phys. Chem. B

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Possible dissociative adsorptions of organic molecules such as CH 3 OH (CH 3 NH 2 ) to form CH 3 O‚‚‚H or CH 3 ‚‚‚OH (CH 3 NH‚‚‚H or CH 3 ‚‚‚NH 2 ) on the Si(100)-2 × 1 surface are discussed by using the hybrid density functional B3LYP method. The Si 9 H 12 cluster is used as a model of the Si(100)-2 × 1 surface. First, a CH 3 -OH adsorbs molecularly on the Si(100)-2 × 1 surface with no barrier and its stabilization energy is estimated to be 14 kcal/mol. Next, the molecularly adsorbed CH 3 OH dissociates to CH 3 O‚‚‚H or CH 3 ‚‚‚OH. The activation energies to form CH 3 O‚‚‚H/Si 9 H 12 and CH 3 ‚‚‚OH/Si 9 H 12 from the molecularly adsorbed CH 3 OH/Si 9 H 12 are calculated to be 3.8 and 27.8 kcal/mol, respectively. The transition states in these reactions lie 10.5 kcal/mol below and 14.0 kcal/mol above the energy of the initial state (isolated bare Si 9 H 12 cluster + CH 3 OH molecule), respectively, and thus the former reaction has no barrier to dissociative chemisorption and will occur under milder conditions than the latter. The overall exthothermicity from initial state is calculated to be 65.3 kcal/ mol in the former reaction, while 80.9 kcal/mol in the latter reaction and thus the product in the latter reaction is more stable than in the former reaction. Therefore, the former reaction would proceed under mild conditions while the latter reaction would proceed under severe conditions. Same results are obtained in the case of the dissociative adsorptions of CH 3 NH 2 on the Si(100)-2 × 1 surface; the dissociatively adsorbed CH 3 NH‚‚‚H/ Si 9 H 12 is more likely to be produced under mild conditions while the dissociatively adsorbed CH 3 ‚‚‚NH 2 / Si 9 H 12 is more likely to be produced under severe conditions. Orbital interactions and charge transfers have been analyzed to clarify the differences of the adsorption mechanisms. Significant negative charge transfer from the silicon surface to the CH 3 OH and CH 3 NH 2 molecules is the main reason these molecules dissociatively adsorb on the silicon surface in a reductive manner.

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ARUPS of water adsorption on Si(100) and Si(111) surfaces

Cited by 26 publications

References 15 publications

Surface S_N2 Reaction by H₂O on Chlorinated Si(100)-2 × 1 Surface

Surface S_N2 Reaction by H₂O on Chlorinated Si(100)-2 × 1 Surface

Ion desorption induced by core-level excitation of H2O/Si(100): Evidence of desorption due to the multielectron excitation/decay

Possible Dissociative Adsorption of CH₃OH and CH₃NH₂ on Si(100)-2 × 1 Surface

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ARUPS of water adsorption on Si(100) and Si(111) surfaces

Cited by 26 publications

References 15 publications

Surface SN2 Reaction by H2O on Chlorinated Si(100)-2 × 1 Surface

Surface SN2 Reaction by H2O on Chlorinated Si(100)-2 × 1 Surface

Ion desorption induced by core-level excitation of H2O/Si(100): Evidence of desorption due to the multielectron excitation/decay

Possible Dissociative Adsorption of CH3OH and CH3NH2 on Si(100)-2 × 1 Surface

Contact Info

Product

Resources

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Surface S_N2 Reaction by H₂O on Chlorinated Si(100)-2 × 1 Surface

Surface S_N2 Reaction by H₂O on Chlorinated Si(100)-2 × 1 Surface

Possible Dissociative Adsorption of CH₃OH and CH₃NH₂ on Si(100)-2 × 1 Surface