Growth process and interfacial structure of epitaxial Y 2O 3/Si thin films deposited by pulsed laser deposition

Abstract

We have proposed the use of YMnO 3 as a ferroelectric layer and of Y 2O 3 as an insulator layer for ferroelectric gate transistor applications. Insertion of the Y 2O 3 layer at the YMnO 3/Si interface significantly improves the crystallinity of the YMnO 3 layer. Although we have used [1 1 1]-oriented Y 2O 3 layers so far, the epitaxially grown Y 2O 3 films have a potential to improve the ferroelectricity of the ferroelectric film. Furthermore, the Y 2O 3 films have a relatively large dielectric constant ( ε=14–17), as well as good thermal stability. However, it still remains unknown what the relationship is between dielectric properties and interfacial structure of epitaxial Y 2O 3/Si films. We have recently succeeded in obtaining epitaxially grown (1 1 1)Y 2O 3 on (1 1 1)Si surface by pulsed laser deposition method. In this report, the relationship between the crystallinity of the Y 2O 3 epitaxial film and the dielectric properties is discussed.