Characterization of selective etching and patterning by sequential light- and heavy-ion irradiation of LiNbO3

The induced selective etching properties of LiNbO3 in a sample subjected to ion processing using sequential light- and heavy-ion irradiation are investigated and discussed. Through the use of TEM and SEM, the lattice structure at the amorphous-crystalline interface is examined after heavy ion exposure and it is found that single-energy amorphizing irradiation results in undercut etching at the interface, while multiple-energy irradiation yields sharper features. Such sequential-irradiation process based on both light- and heavy-ion irradiation enables ready fabrication of concomitant high-resolution patterning and exfoliation of structured freestanding thin films.