Scanning Electron Microscope Observation of Ridge Structures Formed on (100) and (110) Gd 3 Ga 5 O 12 Substrates

Straight ridge patterns about 4 µm high are formed in the [01̄2] direction on a (100)Gd 3 Ga 5 O 12 (GGG) single crystal substrate and in the [11̄2] direction on a (110)GGG substrate by argon ion-beam etching and subsequent soaking in a hot phosphoric acid solution. The ridge shapes are observed with a scanning electron microscope (SEM). The crystal faces, which appear on the ridge side walls, are examined. Although the ridge directions are polar, the ridge cross sections are symmetrical and faces with the same indices appear on both side walls. Side wall roughness is considerably influenced by the accuracy of the ridge direction alignment.