AVS 47th International Symposium
    Dielectrics Thursday Sessions
       Session DI+EL+MS-ThM

Paper DI+EL+MS-ThM1
Oxidation of Clean and H-passivated Silicon by Molecular and Atomic Oxygen

Thursday, October 5, 2000, 8:20 am, Room 312

Session: Ultrathin Dielectrics and Interfaces
Presenter: X. Zhang, Rutgers University
Authors: X. Zhang, Rutgers University
Y.J. Chabal, Bell Laboratories, Lucent Technologies
E. Garfunkel, Rutgers University
S.B. Christman, Bell Laboratories, Lucent Technologies
E.E. Chaban, Bell Laboratories, Lucent Technologies
Correspondent: Click to Email
The need for uniform and ultra-thin silicon oxides in microelectronics requires a fundamental understanding of the initial oxidation of both clean and H-passivated (HF-etched) silicon in oxygen. We have undertaken a systematic infrared absorption study of molecular O@sub 2@ and atomic O oxidation of H-passivated flat and vicinal Si(111) and Si(100) surfaces. Using an IR transmission geometry for full access to Si-O stretch (900-1250 cm@super -1@) and Si-H bending (600-850 cm@super -1@) modes, we can directly observe the incorporation of oxygen even after H-desorption under ultra-high vacuum conditions. Furthermore, hydrogen at steps can be spectrally distinguished from H on terraces, thus making it possible to correlate the kinetics of H elimination with oxide formation as a function of surface structure. We find that upon 1 Torr exposure at 300@super o@C, the bonding of step hydrogen is preferentially altered on the H/Si(111) surface, with dihydride steps being the most reactive. Yet, the rate of oxidation does not scale with the step density, indicating that direct oxidation of terraces takes place simultaneously. For the Si(100) surface, we contrast the oxidation of the HF-etched (atomically rough surface) with that of the smooth H-Si(100)-(2x1) surface prepared in HHV and that of the clean Si(100)- (2x1) surface in order to extract the mechanism for molecular O@sub 2@ dissociation.