Physical characterization of lithium niobate thin films on silicon substrates
Stone, Barbara Ann
Rabson, Thomas A.
Master of Science thesis
The structure and orientation of radio frequency sputtered lithium niobate (LiNbO$\sb3$) films on silicon substrates is determined using x-ray diffraction. The structure of the LiNbO$\sb3$ films is determined to be a strong function of the substrate temperature. The preferred crystal orientation of the film is found to depend on the substrate orientation. Of particular importance is the observation of LiNbO$\sb3$ polycrystalline films oriented with the c axis of the crystallites normal to the surface of $\langle$111$\rangle$ silicon substrates. This result is important since the ferroelectric polarization and photocurrents are directed along the c axis of crystal, making the development of ferroelectric memory devices using LiNbO$\sb3$ possible. Scanning electron microscopy revealed that the films were generally smooth, and no ferroelectric domain contrast was observed. Ellipsometry was used to determine the refractive indices and thicknesses of the films.
Engineering, Electronics and Electrical; Engineering, Materials Science