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

抄録

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 %.