Ion bombardment induced interface broadening in Co/Cu system as a function of layer thickness

It has been shown recently that in case of bilayers ion bombardment induced interface roughening occurs if the sputtering yields of the adjacent layers are strongly different. Now we checked the effect of this mechanism on AES depth profiling if the thickness at least one of the layers is small compared to the thickness of ion mixed layer. It turned out that in this case the ion bombardment induced interface roughening is negligible, since the ion mixing eliminates the differences of the sputtering yields.