Scanning electron microscopy observation in wide field of view for SrO/TiO2-terminated step-terrace structure formed on SrTiO3(001) single crystal surface

SrO-terminated terraces were formed along TiO2-terminated step edges by annealing (001) surfaces of SrTiO3 single crystal originally with step-terrace structure fully terminated at TiO2 atomic layer. The prepared step-terrace structure with the two different terminations were visualized in a wide field of view using scanning electron microscopy (SEM) under a low acceleration voltage of 1 kV and a short working distance of 2 mm. The different termination was clearly identified by an in-column secondary electron detector even in the wide-field region with dimensions of 30 × 30 µm2. As results, the uniformity of the step-terrace structure was found to be limited only at a localized area. The wide-field observation revealed that there exist many “step-defects” such as pinning of the step lines and wandering so large that it goes around to an opposite side. Step-defects were present in at least several for 30 × 30 µm2 sized observation areas with a probability of about 60 %.