Deposition, characterization, and applications of thin film lithium niobate

Ferroelectric thin films of lithium niobate have been epitaxially grown on a variety of silicon and gallium arsenide substrates by reactive r.f. sputtering. The deposition process was optimized by independently varying the substrate temperature, oxygen-argon ratio, target mixture, substrate type, and deposition times. The results of these tests are presented. The lithium niobate thin films were structurally analyzed using Bragg x-ray diffraction (XRD) and scanning electron microscopic (SEM) techniques to determine their orientation, grain size, and domain structure. Electrical characterization included C-V measurements utilized to calculate the permittivity, I-V to obtain the resistivity, and photocurrent measurements to verify the existence of a bulk photovoltaic and pyroelectric effect in the thin films. In addition, preliminary results on prefabricated devices are presented as well as a review of the pertinent effects and potential device applications based on thin films of lithium niobate.