Atomic layer deposition of ferroelectric complex oxide thin films

Advanced technologies derive many of their capabilities from the advanced materials that they are made from. Complex oxides are a class of materials which are driving technological advancement in a host of different directions. These highly functional materials have a great variety of useful properties, which can be chosen and even engineered through careful choice of material. Advanced materials require advanced deposition methods. Atomic layer deposition (ALD), a variant of chemical vapor deposition (CVD), is gaining more use in industry for its ability to provide ultra-high film thickness res- olution (down to 0.1 nm), capability to conformally coat three-dimensional structures, and its high uniformity across large surface areas. Additionally, ALD processes provide a possibility to improve economic and environmental viability of the process as compared to CVD by using and wasting less toxic reactants and expelling fewer nano-particulate byproducts. ALD processes are highly mature for many binary oxides commonly used in the semiconductor industries, however processes for depositing heavy metal oxides and complex oxides — oxides containing two or more separate metallic cations — are sorely lacking in literature. The primary focus of this work is the development of a process for deposit- ing the complex perovskite oxide lead titanate (PbTiO3), an end group of the lead zirconate titanate family (PbZrxTi1-xO3), which has valuable technical ap- plications as well as serves as a template for applying this research into other material systems. The author gratefully acknowledges the Army Research Office (ARO) for their support of this project under the funding provided by Grant # W911NF- 08-1-0067.