Effects of Substrate Temperature on Helium Content and Microstructure of Nanocrystalline Titanium Films

Helium-charged nanocrystalline titanium films have been deposited by He--Ar magnetron co-sputtering. The effects of substrate temperature on the helium content and microstructure of the nanocrystalline titanium films have been studied. The results indicate that helium atoms with a high concentration are evenly incorporated in the deposited titanium films. When the substrate temperature increases from 60°C to 350°C while the other deposition parameters are fixed, the helium content decreases gradually from 38.6 at.% to 9.2 at.%, which proves that nanocrystalline Ti films have a great helium storage capacity. The 2θ angle of the Bragg peak of (002) crystal planes of the He-charged Ti film shifts to a lower angle and that of (100) crystal plane is unchanged as compared with that of the pure Ti film, which indicates that the lattice parameter c increases and a keeps at the primitive value. The grain refining and helium damage result in the diffraction peak broadening.