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US 6,686,236 B2Granted
Methods of preventing reduction of IrOx during PZT formation by metalorganic chemical vapor deposition or other processing
AssigneesTexas Instruments Incorporated, Agilent Technologies, Inc.
InventorsSanjeev Aggarwal, Stephen R. Gilbert, Scott R. Summerfelt
Life of this patent
Estimating the term…
Abstract
A method of fabricating a ferroelectric capacitor is disclosed. The method comprises the decreases a reduction in a bottom electrode material during formation of the ferroelectric dielectric portion of the capacitor. In the above manner, a fatigue resistance of the ferroelectric capacitor is increased substantially.
Claims14
A method of forming an FeRAM capacitor, comprising:
- forming an over-oxygenated conductive oxide film as at least a portion of a bottom electrode layer over a substrate, wherein forming the over-oxygenated conductive oxide film comprises:
- establishing an oxygen environment of about 40-50% oxygen within a deposition chamber;
- reducing a film deposition rate of the portion of the bottom electrode layer from a first, rate to a second, slower rate in the oxygen environment for a predetermined period of time, wherein the conductive oxide film contains a larger amount of oxygen therein than would otherwise reside therein at the first, conventional deposition rate within the predetermined period of time;
- forming a ferroelectric dielectric layer over the over-oxygenated conductive oxide film;
- and
- forming a top electrode layer over the ferroelectric dielectric layer.
3 more elements
A method of forming an FeRAM capacitor, comprising:
- forming an over-oxygenated conductive oxide film as at least a portion of a bottom electrode layer over a substrate, wherein forming an over-oxygenated conductive oxide film comprises:
- establishing an Ar/O2 environment within a sputter deposition chamber, wherein O2 comprises about 40% or more and about 50% or less of the Ar/O2 environment;
- and
- performing a reactive sputtering deposition using an iridium (Ir) target to form the over-oxygenated iridium oxide film having a deposition rate of about 5 Angstroms/second or more and about 10 Angstroms/second or less for a predetermined period of time to generate the over-oxygenated iridium oxide film having a thickness of about 10 nm or more and about 100 nm or less;
- forming a ferroelectric dielectric layer over the over-oxygenated conductive oxide film;
- and
- forming a top electrode layer over the ferroelectric dielectric layer.
4 more elements
A method of forming an FeRAM capacitor, comprising:
- forming an over-oxygenated conductive oxide film as at least a portion of a bottom electrode layer over a substrate, wherein forming an over-oxygenated conductive oxide film comprises:
- establishing an Ar/O2 environment within a sputter deposition chamber, wherein O2 comprises about 60% or more and about 70% or less of the Ar/O2 environment;
- and
- performing a reactive sputtering deposition using an iridium (Ir) target to form the over-oxygenated iridium oxide film having a deposition rate of about 10 Angstroms/second or more and about 20 Angstroms/second or less for a predetermined period of time to generate the over-oxygenated iridium oxide film having a thickness of about 10 nm or more and about 100 nm or less;
- forming a ferroelectric dielectric layer over the over-oxygenated conductive oxide film;
- and
- forming a top electrode layer over the ferroelectric dielectric layer.
4 more elements
A method of forming an FeRAM capacitor, comprising:
- forming an over-oxygenated conductive oxide film as at least a portion of a bottom electrode layer over a substrate, wherein forming an over-oxygenated conductive oxide film comprises:
- establishing an Ar/O2 environment within a sputter deposition chamber, wherein O2 comprises about 40% or more and about 50% or less of the Ar/O2 environment;
- establishing a temperature at the substrate of about 25° C. or more and about 270° C. or less;
- and
- performing a reactive sputtering deposition using an iridium target to form the over-oxygenated iridium oxide film having a deposition rate of about 10 Angstroms/second or more and about 20 Angstroms/second or less for a predetermined period of time to generate the over-oxygenated iridium oxide film having a thickness of about 10 nm or more and about 100 nm or less;
- forming a ferroelectric dielectric layer over the over-oxygenated conductive oxide film;
- and
- forming a top electrode layer over the ferroelectric dielectric layer.
5 more elements
A method of forming an FeRAM capacitor, comprising:
- forming an iridium layer over a substrate;
- forming an over-oxygenated iridium oxide layer over the iridium layer, wherein the iridium layer and the over-oxygenated iridium oxide layer together form a bottom electrode for the FeRAM capacitor, wherein forming the over-oxygenated iridium oxide layer comprises forming the over-oxygenated iridium oxide layer via reactive sputtering in a sputtering chamber having an Ar/O2 environment, wherein the O2 comprises about 40% or more and about 50% or less of the Ar/O2 environment, and wherein a deposition rate of the over-oxygenated iridium oxide layer is less than about 10 Angstroms/second, and wherein the deposition continues until the over-oxygenated iridium oxide layer attains a thickness of about 10 nm or more and about 100 nm or less;
- forming a ferroelectric dielectric layer over the over-oxygenated iridium oxide layer, wherein oxygen diffuses out of the over-oxygenated iridium oxide layer during the formation of the ferroelectric dielectric layer, and reducing to iridium oxide;
- and
- forming a top electrode layer over the ferroelectric dielectric layer.
2 more elements
A method of forming an FeRAM capacitor, comprising:
- forming an iridium layer over a substrate;
- forming an over-oxygenated iridium oxide layer over the iridium layer, wherein the iridium layer and the over-oxygenated iridium oxide layer together form a bottom electrode for the FeRAM capacitor, wherein forming the over-oxygenated iridium oxide layer comprises forming the over-oxygenated iridium oxide layer via reactive sputtering in a sputtering chamber having an Ar/O2 environment, wherein the O2 comprises about 60% or more and about 70% or less of the Ar/O2 environment, and wherein a deposition rate of the over-oxygenated iridium oxide layer is about 10 Angstroms/second or more and about 20 Angstroms/second or less, and wherein the deposition continues until the over-oxygenated iridium oxide layer attains a thickness of about 10 nm or more and about 100 nm or less;
- forming a ferroelectric dielectric layer over the over-oxygenated iridium oxide layer, wherein oxygen diffuses out of the over-oxygenated iridium oxide layer during the formation of the ferroelectric dielectric layer, and reducing to iridium oxide:
- and
- forming a top electrode layer over the ferroelectric dielectric layer.
2 more elements
A method of forming an FeRAM capacitor, comprising:
- forming an iridium layer over a substrate;
- forming an over-oxygenated iridium oxide layer over the iridium layer, wherein the iridium layer and the over-oxygenated iridium oxide layer together form a bottom electrode for the FeRAM capacitor, wherein forming the over-oxygenated iridium oxide layer comprises forming the over-oxygenated iridium oxide layer via reactive sputtering in a sputtering chamber having an Ar/O2 environment, wherein the O2 comprises about 40% or more and about 50% or less of the Ar/O2 environment, and wherein a deposition rate of the over-oxygenated iridium oxide layer is about 10 Angstroms/second or more and about 20 Angstroms/second or less, and wherein the deposition occurs at a substrate temperature of about room temperature or more and about 270° C. or less, and further wherein the deposition continues until the over-oxygenated iridium oxide layer attains a thickness of about 10 nm or more and about 100 nm or less;
- forming a ferroelectric dielectric layer over the over-oxygenated iridium oxide layer, wherein oxygen diffuses out of the over-oxygenated iridium oxide layer during the formation of the ferroelectric dielectric layer, and reducing to iridium oxide;
- and
- forming a top electrode layer over the ferroelectric dielectric layer.
2 more elements
Dependencies are inferred from the claim text.