Investigations of helium incorporated into a film deposited by magnetron sputtering

Helium-containing titanium film was prepared by magnetron sputtering in a gas mixture of helium and argon. This method distinctly differs from traditional helium introduction into metals. A high concentration of helium up to 45 at.% and a uniform distribution in the bulk were shown by ion beam analysis. The process of helium incorporation is considered in which the helium particles are energetically backscattered from the target, fly through the glow discharge zone and are consequently embedded into the growing film. It is virtually a continuous sub-threshold-energy implantation during film deposition based on the plasma technique. The limited partial pressure of argon is to maintain the discharge and sputter the titanium target. The helium content incorporated can be controlled conveniently by adjusting the pressure of the working gases. X-ray diffraction, transmission electron microscopy, Doppler broadening of positron beam analysis and thermal helium desorption spectroscopy revealed the microstructure of titanium films, the state of helium bubbles, the defect characteristic related to helium and thermal release behaviour of helium from the titanium film