A bevel has been etched in a GaAs epitaxial film grown on a Si substrate, so that the Raman spectrum of the GaAs layers can be measured as a function of distance from the GaAs/Si interface. The amount of strain and disorder in the GaAs film has been estimated from the GaAs longitudinal optical phonon line shape and frequency. Both the strain and the amount of disorder were found to decrease with increase in the distance from the interface.