Epitaxial oxide thin films on Si(001)

Abstract

Over the years, the development of epitaxial oxides on silicon has been a great technological challenge. Amorphous silicon oxide layer forms quickly at the interface when the Si surface is exposed to oxygen, making the intended oxide heteroepitaxy on Si substrate extremely difficult. Epitaxial oxides such as BaTiO3 (BTO) and SrTiO3 (STO) integrated with Si are highly desirable for future generation transistor gate dielectric and ferroelectric memory cell applications. In this article, we review the recent progress in the heteroepitaxy of oxide thin films on Si(001) substrate by using the molecular beam epitaxy technique at Motorola Labs. Structural, interfacial and electrical properties of the oxide thin films on Si have been characterized using in situ reflection high energy electron diffraction, x-ray diffraction, spectroscopic ellipsometry, atomic force microscopy, Auger electron spectroscopy, x-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, high-resolution transmission electron energy loss spectroscopy, capacitance–voltage and current–voltage measurement. We also present the transistor results and address the impact of the epitaxial oxide films on future generation metal-oxide-semiconductor field effect transistors.