Preferred crystal orientation of hafnium films prepared by ion beam assisted deposition

Hafnium (Hf) films with different preferred crystalline orientation have been prepared on Si(1 1 1) by ion beam assisted deposition (IBAD) at room temperature. The effects of the Ar+ ion incidence angle and the ion/atom arrival ratio on the texture were investigated. Hf films deposited by vacuum electron-beam evaporation have polycrystalline orientations. Hf films deposited by sputtering method, with the deposition rate about 0.15 nm/s, have weak (1 1 0) orientations. Hf films have preferred (1 1 0) orientation when the growing films were bombarded by 500 eV Ar+ ions with the incidence angle of 75 deg. and current density of 90 μA/cm2 with the ion/atom arrival ratio about 0.21. However, as the current density was beyond 120 μA/cm2 with the ion/atom arrival ratio about 0.43, the Hf films exhibited mixed (0 0 2) and (1 0 0) orientations and which were independent of the ion incident angle. The preferred orientation of Hf films is determined by the competition between the surface energy and the strain energy