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

[0007] Another feature of the present invention is to provide a dielectric that has an increased thermodynamic stability at the substrate / dielectric interface.

[0008] A further feature of the present invention is to provide a low temperature reaction to prevent or reduce oxide diffusion into the substrate when making the dielectric.

[0009] An additional feature of the present invention is to provide a low temperature reaction to prevent reaction of the substrate with impurities or solvents when making the dielectric.

[0010] Also, a feature of the present invention is to provide a high mobility / diffusion coefficient during film formation to promote rapid reaction.

[0012] Yet another feature of the present invention is to provide a dielectric film that is uniform, coherent, and stable.

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.