Si Atomic Layer Epitaxy Based on Si2H6 and Remote He Plasma Bombardment
TEXAS UNIV AT AUSTIN DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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Atomic layer EpitaxyALE of silicon has been demonstrated by using remote helium plasma low energy bombardment to desorb H from a H-passivated Si100 surface at low temperatures and subsequently chemisorbing disilane on the surface in a self limiting fashion in a Remote Plasma Chemical Vapor DepositionRPCVD system in which the substrate is downstream from an r-f noble gasHe or Ar glow discharge in order to minimize plasma damage. It was found necessary to desorb the H from the Si surface to create adsorption sites for Si bearing species such as Si2H6. Optimal He bombardment parameters were to be 30 W at 100 mTorr He at 400 deg C for 1-3 min. Helium was found to be more effective than Ar bombardment because of the closer match of the He and H masses compared to that between Ar and H. Monte Carlo TRIM simulations of He and Ar bombardment of H-terminated Si surfaces were performed to validate this hypothesis and to predict that approximately 3 surface H atoms are displaced by the incident He atoms, with no Si atom displacement for the energies in the range of 15-60 eV. Alternate Si2H6 dosing and He low energy bombardment cycles -100-200 were performed to confirm ALE-mode of growth. It was found that the growth per cycle saturates with long Si2H6 dosing at a level which increases with He bombardment time. Silicon, Disilane, Atomic layer epitaxy, He Plasma.
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy
- Plasma Physics and Magnetohydrodynamics