Amorphization and recrystallization of Hf-implanted LiNbO3

Abstract

Hf+ implantation at 150 keV with a dose of 1015 cm2 in LiNbO3 has been shown to produce a complete amorphization of the surface layer. The damaged layer thickness of ~ 600 Å increases with annealing temperature in air for temperatures above ~ 700 °C and reaches 1000 Å at 900 °C. On the other hand, channeling experiments show a recovery of crystallinity starting at about 500 °C and becoming complete at 900 °C. However, the channeling directions are different for both the Nb surface layer and the LiNbO3 bulk (except for the Ȳ011̄0〉 axis normal to the crystal face). 7Li(p, α)4 He nuclear reaction experiments have been performed to monitor the Li profile caused by the annealing treatments. It has been ascertained that about 75% of the total Li content in the crystal is lost at ~ 900 °C when crystallinity is recovered. It is suggested that LiNb3O8 is formed by regrowth of the surface layer.