Investigations on ion implantation-induced strain in rotated Y-cut LiNbO3 and LiTaO3 *

The monocrystalline LiNbO3 (LN) and LiTaO3 (LT) plates have been qualified as a kind of material platform for high performance RF filter that is considerable for the 5G communication. LN and LT thin films are usually transferred on handle wafers by combining ion-slicing and wafer bonding technique to form a piezoelectric on insulator (POI) substrate. The ion implantation is a key process and the implantation-induced strain is essential for the layer transfer. Here, we reported the strain profile of ion implanted rotated Y-cut LN and LT. The ion implantation generates the out-of-plane tensile strain of the sample surface and (006) plane, while both the tensile and compressive strain are observed on the (030) plane. The implanted ions redistributed due to the anisotropy of LN and LT, and induce the main tensile normal to the (006) plane. Meanwhile, the (030) planes are contracted due to the Poisson effect with the interstitial ions disturbing and mainly show a compressive strain profile.