Tailoring strain in the SrTiO3 compound by low-energy He+ irradiation

The ability to generate a change of the lattice parameter in a near-surface layer of a controllable thickness by ion implantation of strontium titanate is reported here using low-energy He+ ions. The induced strain follows a distribution within a typical near-surface layer of 200 nm as obtained from structural analysis. Due to the clamping effect from the underlying layer, only perpendicular expansion is observed. Maximum distortions up to 5–7% are obtained with no evidence of amorphisation at fluences of 1016 He+ ions/cm2 and ion energies in the range 10–30 keV.