Epitaxial growth of orientation-controlled KNbO3 crystal films on MgO using KTaxNb1-xO3 intermediate layer by metalorganic chemical vapor deposition

In this letter, we report a method to obtain an orientation-controlled (010 ) KNbO3 crystal film on (110) MgO substrate based on the epitaxial growth b y the low-pressure metalorganic chemical vapor deposition. In order to cont rol the orientation of the KNbO3 film, an intermediate layer of KTaxNb1-xO3 was used. In the case where the Ta/(Ta+Nb) ratio of the KTaxNb1-xO3 film w as over 40%, we could obtain (010)-oriented epitaxial KNbO3 films. Furtherm ore, the surface morphology of the deposited film, the thickness of which w as about 1 mum, was smooth at the Ta/(Ta+Nb) ratio of 60%. The measurement of the refractive index dispersion of the KNbO3 crystal film was also carri ed out. (C) 2001 American Institute of Physics.