PROGRAM TITLE: Electronic and Photonic Ceramics

Principal Investigator(s):

NIST Staff:

Designated Project Leader:

Kaiser, Debra L.
Mailing Address:
NIST
Materials (223), A329
Gaithersburg, MD 20899
Telephone: (301) 975-6759
FAX Number: (301) 990-8729
E-mail Address: dkaiser@enh.nist.gov

Other NIST Principal investigator(s):

Rotter, Lawrence D.
Mailing Address:
NIST
Materials (223), A329
Gaithersburg, MD 20899
Telephone: (301) 975-6603
FAX Number: (301) 990-8729
E-mail Address: rotter@enh.nist.gov

Technical Description:

This project involves a study of the complex relationships between thin film deposition, microstructural features and electro-optical properties of barium titanate thin films deposited by by metalorganic chemical vapor deposition (MOCVD). Novel electro-optical measurement methodology is under development to determine the crystallographic orientation and polarization state of the thin films.

Technical Objective:

The objectives are to address key scientific issues vital to the advancement of ferroelectric oxide- based thin film photonic devices for information technology and communications industries and to develop appropriate measurement methodology as needed to study these issues.

Outcome:

The outcome will be the establishment of microstructural characterization and electro-optical measurement techniques needed to develop the processing/structure/property relationships of importance for ferroelectric oxide thin films for photonic devices.

Accomplishments:

A thermal MOCVD system, designed and built at NIST for ferroelectric oxide film deposition, has been modified to include an oxygen preheater and metalorganic bubblers with improved temperature control. These modifications have improved the reproducibility of the deposition experiments. A set of processing conditions has been established for the deposition of epitaxial BaTiO₃ films on single crystal MgO and KTaO₃ substrates in the modified system.

X-ray diffraction studies showed that the BaTiO₃ films could contain either epitaxial, polycrystalline or amorphous material, or a combination of epitaxial and amorphous or polycrystalline and amorphous phases. Second harmonic generation (SHG) in the films was measured as a function of the incidence angle of the fundamental beam as well as the direction of polarization of the fundamental beam. The SHG data on the as-grown films were not relatable to either the microstructure or the crystallographic orientation of the BaTiO₃ grains. Thus, SHG was shown not to be a viable technique for determining the orientation of BaTiO₃ thin films, despite contrary reports in the literature.

Outputs:

Technical Papers:

"Epitaxial growth of BaTiO₃ thin films at 600 ^oC by metalorganic chemical vapor deposition", D. L. Kaiser, M. D. Vaudin, L. D. Rotter, Z. L. Wang, J. P. Cline, C. -S Hwang, R. B. Marinenko, and J. G. Gillen, Appl. Phys. Lett 66, 2801 (1995).