FIB milling of single-crystal and sputtered ZnO: SEM and AFM characterization

We report on the morphological study of focused ion beam (FIB) milling of both sputter-deposited and
single crystal (0001) ZnO substrates. The surface roughness and the FIB induced sputtering yield were
measured as a function of the ion dose and angle. Smoothing effect of rough films deposited by sputtering
has been found at low ion doses. FIB milling at non-normal incidence produced roughness increase and
the formation of ordered terraces on (0001)-oriented sputtered ZnO. Conversely, surface roughness and
FIB yield on single crystal ZnO substrates is basically unaffected by ion dose and milling angle.