  High reflective coatings are used in many physics experiments. Despite the
high quality of the opticalcoating, the performances of the mirrors is altered
by the scattered light induced by micrometers sizedefects in the coating
layers. The topic of this paper is the study of the point-like scatterers
present in thespecific coating of the mirrors used in state of the art, high
sensitivity optical experiments. We studied thebehavior of the materials
according to different thicknesses, and how the defects change after
annealing.To our knowledge, this is a first insight into the formation of such
defects for different materials andthickness and how this is reduced when
samples are annealed.
