Origin of intrinsic stress in Y2O3 films deposited by reactive sputtering

Abstract

Microstructural evolution and preferred orientation change of radiofrequencymagnetron sputtered ZnO thin films Y 2 O 3 thin films were deposited by reactive sputtering of an Y target in an Ar and O 2 gas mixture. Intrinsic stresses and the Ar content in the films were measured by the sine square psi method of x-ray diffraction and wavelength dispersive spectrometer, respectively. At low working pressures the films had high compressive stresses. As working pressure increased, compressive stress was relaxed. Ar content was high in the film that had high compressive stress. After annealing of the films at 700°C, the compressive stress was largely relaxed but the Ar content remained unchanged. These results clearly showed that compressive stress in Y 2 O 3 films was not caused by Ar entrapment as an impurity but by Ar bombardment. Intrinsic stress was almost independent of the O 2 /Ar flow ratio, showing that O bombardment was equal to Ar bombardment in affecting the intrinsic stress in Y 2 O 3 films. The independence of intrinsic stress with the O 2 /Ar flow ratio was explained by the concept of M i 1/2 ͕͓M i cos Ϯ͑M t 2 ϪM i 2 sin 2 ͒ 1/2 ͔/(M i ϩM t )͖ instead of the M t /M i ratio, where M t is the atomic mass of the target material, M i is the atomic mass of the sputtering gas, and is the scattering angle.

Catalyst-Enhanced Chemical Vapor Deposition of Yttrium Oxide

“…Yttrium oxide (Y 2 O 3 ) thin films have potential applications as electronic insulators, optical or magneto-optical materials, protective coatings, and reaction barriers. − Yttria is also an important component in a wide variety of materials such as yttria-stabilized zirconia (YSZ), yttrium−aluminum or yttrium−indium garnet (YAG or YIG), the perovskite phase YTiO 3 , and, especially, yttrium-based high conducting temperature superconducting metal oxide materials …”