AMORPHIZATION AND RECRYSTALLIZATION OF HF-IMPLANTED LINBO3

Hf+ implantation at 150 keV with a dose of 10(15) cm-2 in LiNbO3 has been shown to produce a complete amorphization of the surface layer. The damage layer thickness of approximately 600 angstrom increases with annealing temperature in air for temperatures above approximately 700-degrees-C and reaches 1000 angstrom at 900-degrees-C. On the other hand, channeling experiments show a recovery of crystallinity starting at about 500-degrees-C and becoming complete at 900-degrees-C. However, the channeling directions are different for both the Nb surface layer and the LiNbO3 bulk (except for the <0110BAR> axis normal to the crystal face). Li-7(p, alpha)He-4 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 approximately 900-degrees-C when crystallinity is recovered. It is suggested that LiNb3O8 is formed by regrowth of the surface layer.