Abstract

The use of sputtering techniques in order to obtain single crystal film has attracted wide interest recently due to the relative simplicity of the process and of the systems involved. Nevertheless, the quality of the film has a strong dependence on the parameters related to the deposition process. We have studied the influence of the main parameters, namely, the substrate temperature, the rf sputtering power, the total gas pressure, and the oxygen/argon ratio. LiNbO₃ was deposited on three types of substrate: Corning glass, quartz, and sapphire. We also examined the influence of postsputtering annealing. The analyses included reflected electron diffraction, Auger electron spectroscopy, and laser beam coupling. It was found that the substrate temperature plays a main role for all three substrates. Its variation enabled the control of the crystalline structure, which was random polycrystalline film on the Corning glass, oriented polycrystalline on the quartz substrate, and single crystal on the sapphire. Optimal fabrication parameters for the last case are reported. Annealing of the substrate improved the results further, and sharp electron diffraction dots of LiNbO₃ with the c axis parallel to the substrate surface were observed. A He-Ne laser beam was coupled into the layers via a prism coupler, and guided light mode attenuation was measured.

© 1985 Optical Society of America