Thin film dielectrics with perovskite structure and preparation thereof

Abstract

Methods of making a ternary oxide and a perovskite-related ternary oxide structure are described. The methods include reacting a binary oxide with a metal oxide or a metal hydroxide to form a ternary oxide dielectric layer on a substrate. Powders, anodes, pressed articles, and capacitors including the ternary oxide or perovskite-related ternary oxide structure as a dielectric layer or other layers are further described.

Description

[0001] This application claims the benefit under 35 U.S.C. §119(e) of prior U.S. Provisional Patent Application No. 60 / 495,220 filed Aug. 14, 2003, which is incorporated in its entirety by reference herein.BACKGROUND OF THE INVENTION [0002] The present invention relates to perovskite-related materials and methods to make a perovskite-related structure, as well as to methods of making ternary oxide dielectric films and capacitors and other devices containing the films. [0003] Dielectric films or layers are used in a variety of applications, such as anode production and capacitors. Typically, dielectric films comprised of binary metal oxides, such as Ta2O5 and Nb2O5, are formed on a metal substrate creating a metal-metal oxide interface. However, when using binary metal oxides, such as Ta2O5 and Nb2O5, the binary metal oxide can break down to form undesirable metal oxides, such as NbO2, which can then diffuse across the interface into the metal anode, for instance. This is especially ...

AI Technical Summary

Benefits of technology

The present invention provides a method of making a ternary oxide dielectric layer on a substrate. The ternary oxide dielectric has increased thermodynamic stability at the substrate / dielectric interface, low temperature reaction to prevent oxide diffusion into the substrate, low mobility / diffusion coefficient during film formation, reasonable dielectric constant to promote ionic surface reactions, and high uniformity and coherency. The method includes reacting a binary oxide with a metal oxide, metal hydroxide, metal carbonate, or metal nitrate to form the ternary oxide dielectric. The invention also provides substrates with ternary oxide films and articles using or having the same.

Problems solved by technology

However, when using binary metal oxides, such as Ta2O5 and Nb2O5, the binary metal oxide can break down to form undesirable metal oxides, such as NbO2, which can then diffuse across the interface into the metal anode, for instance.

Moreover, the method for making the binary metal oxides generally involves several steps, which increases production costs.

First, a thermodynamic instability can exist between the substrate and the binary oxide dielectric interface, which often results in the formation of intermediate oxides.

As a result of intermediate oxide formation, oxygen vacancies promote oxide-ion migration, which can affect the critical performance characteristics of the host device.

Second, surface films of binary metal oxides often degrade, which affect the performance of devices into which the films are incorporated.