| AVS 55th International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS2-TuA |
| Session: | Dynamics and Novel Probes |
| Presenter: | I.A. El-Kholy, Old Dominion University |
| Authors: | I.A. El-Kholy, Old Dominion University H. Elsayed-Ali, Old Dominion University |
| Correspondent: | Click to Email |
Surface morphology during the growth of Si on Si(111)-(7x7) by femtosecond pulsed laser deposition (fsPLD) is studied using reflection high-energy electron diffraction (RHEED) at different temperatures. The growth of Si on Si(111) has received considerable attention as a model system of homoepitaxy. PLD is a deposition technique that uses much more energetic species (atoms and ions) compared to other physical vapor deposition (PVD), such as in molecular beam epitaxy. In PLD, the deposition process consists of periodic bursts of laser-generated plume followed by uninterrupted surface relaxation. This periodic nature of deposition differs from other PVD methods, and this could affect the growth mechanism. The use of ultrafast lasers vaporizes the target rather than melting it, thus minimizes the formation of particulates. In this work, in situ RHEED was used to study the dynamics of PLD of Si on Si(111)-(7×7). A Ti-sapphire laser (100-fs, 800-nm, 1 kHz) was used to ablate the Si target to generate a plume that deposite on a Si(111)-(7x7) kept at varying temperatures. The experiment was performed in an ultrahigh vacuum chamber at a residual gas pressure of 5x10-9 torr. It is observed that the decay of the RHEED pattern during deposition is due to the increase in the surface roughness. Epitaxial growth of Si/Si(111)-(7x7) at temperatures as low as 350°C was observed. For this substrate temperature, no change in RHEED patterns was observed after growth, with only reduction in intensity during deposition. This indicates that the growth mechanism was step-flow.