Minimization of amorphous layer in Ar+ ion milling for UHR-EM

► We study the effect of Ar+ ion milling parameters on standard TEM sample quality. ► We introduce interlocking as a parameter for the evaluation of TEM sample quality. ► The resulting amorphous layer thickness and interlocking are directly proportional to the acceleration voltage of the ion beam. ► Preparation time is indirectly proportional to the incident angle of the ion beam. ► Model approximations fit the experimental data very well at low voltage and angle.