1 / 25

Initial Oxidation Reactions of Si(100) Surface by Atomic Oxygen

Initial Oxidation Reactions of Si(100) Surface by Atomic Oxygen. Cheol Ho Choi a and Mark S. Gordon b a Department of Chemistry, Kyungpook National University, Taegu and b Ameslab, Ames, IA 50011. 2x1 Reconstruction of Si(100) Surface. Possible Products. Surface Oxidation and Etching.

alida
Download Presentation

Initial Oxidation Reactions of Si(100) Surface by Atomic Oxygen

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Initial Oxidation Reactions of Si(100) Surface by Atomic Oxygen Cheol Ho Choia and Mark S. Gordonb aDepartment of Chemistry, Kyungpook National University, Taegu and bAmeslab, Ames, IA 50011

  2. 2x1 Reconstruction of Si(100) Surface

  3. Possible Products

  4. Surface Oxidation and Etching

  5. Initial Reaction Mechanism Symmetric (C2v) Asymmetric (Cs)

  6. Initial Surface Products On-dimer Symmetric approach On-Top Asymmetic approach

  7. Passive Oxidation of Si Surface O atom + Silicon Surface Oxidized Surface 1) O has a triplet ground State, 3P2 2) Oxidized surface has a singlet ground state 3) Possibility of intersystem crossing ? How important it is?

  8. Theoretical Details • 9-Si model Used • CASSCF(6,5)/6-31G* for SOC • SOC using the full Breit-Pauli Hamiltonian • ROHF/6-31G* for Direct Dynamics • All calculations are done with GAMESS

  9. Atomic Oxygen Levels

  10. Minimum energy path of Cs triplet surface is attractive.Is low symmetric approach of triplet surface all attractive?

  11. q Incident angle for Direct Dynamics

  12. Angle=0 and 0.5eV kinetic Energy 71.5 fs

  13. Angle=10 and 0.5eV kinetic Energy 78.3 fs

  14. Angle=30 and 0.5eV kinetic Energy 82.9 fs 150 fs

  15. Angle=60 and 0.5eV kinetic Energy 301 fs

  16. From a IRC point and 0.5eV kinetic Energy 29.7 fs 90.9fs

  17. Conclusions • C2v has a repulsive triplet surface • Cs has attractive singlet and triplet surfaces which are nearly identical indicating better chance of intersystem crossing • Even though Cs channel has an attractive triplet surface, it has a very narrow attractive region • SOC must occur to yield products.

  18. Acknowledgements • Prof. M. S. Gordon • Dr. M. Schmidt • KOSEF, KRF

More Related