Real-Time Observation of Ellipsometry Oscillation during GaAs Layer by Layer Growth by Metalorganic Vapor-Phase Epitaxy

Abstract
Ellipsometry oscillations during GaAs metalorganic vapor-phase epitaxy on GaAs (001) substrates were observed. The ellipsometric signal was found to oscillate at a period corresponding to 1 monolayer of GaAs growth. Excellent agreement was seen between growth rate data from oscillation period and those from thickness measurements after growth (deviation: <1%). Oscillation clearly depends on growth temperature and source gas material. The results suggest that ellipsometry oscillation originates from the absorption of probe light by Ga-alkyl bonds at the edges of 2-dimensional islands.