Figure 13

AFM image (a) shows four holes marked as I, II, III and IV which were cut under the 400 \(\upmu \mathrm{N}\) pressing load by phase difference modulations with the self-excitation cutting method. The four holes were cut while the resistance values in the phase shifter circuit were set at 15 \(\mathrm{k}\Omega \), 20 \(\mathrm{k}\Omega \), 25 \(\mathrm{k}\Omega \) and 30 \(\mathrm{k}\Omega \), respectively. Four lines \(\textcircled {1}\)–\(\textcircled {4}\) in the upper corner are to indicate the locations taken for the sectional views of four holes shown in Fig. 2 in Appendix C and the intersecting sectional views are centered on all holes. (b–e) show the magnified depiction for the AFM image of each hole.