US6010927A
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Method for making a ferroelectric device having a tantalum nitride barrier layer
Assignee: NXP USA Inc
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Filing: 1997-10-28
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Granted: 2000-01-04
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Expires: 2017-10-28
Abstract
Abstract A method for forming CMOS transistors and ferroelectric capacitors on a single substrate (10) with improved yield begins by forming CMOS transistors (37a, 37b, 40, 42). A hydrogen anneal using 4-5% hydrogen and a remainder nitrogen is performed to reduce dangling atomic bonds at the gate dielectric/substrate interface of the transistors (37a, 37b, 40, 42). A silicon nitride layer (48) is then deposited over the transistors and on the backside of the wafer substrate (10) in order to substantially encapsulate the effects of the hydrogen anneal to the CMOS transistors (37a, 37b, 40, 42). Ferroelectric capacitor layers (54, 58, 60, 62, 64) are formed overlying the nitride layer (48) where the ferroelectric capacitor layers (54, 58, 60, 62, 64) are oxygen annealed in pure O 2 . The nitride layer (48) prevents the transistor hydrogen anneal from damaging the ferroelectric material by containing the hydrogen.
Inventors
- 👤 Robert E. Jones, Jr.
- 👤 Peir-Yung Chu
- 👤 Peter Zurcher
- 👤 Ajay Jain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:33
CPC Classifications
H; H10; H10B; H10B53/00; H10B53/30; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/682; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/02; H10D84/03; H10D84/038; H10D84/80; H10D84/811; H10D88/00; H10D88/01; H10D84/813
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
72 words
A method for forming a semiconductor device, the method comprising the steps of: forming a plurality of transistors overlying a substrate; forming a barrier layer overlying the plurality of transistors; forming ferroelectric capacitors overlying the barrier layer; forming a plurality of contact openings between the ferroelectric capacitors and the plurality of transistors; and electrically coupling the ferroelectric capacitors to the plurality of transistors using a conductive layer comprising tantalum nitride and aluminum.
Claim 2
Independent Claim
72 words
A method for forming a semiconductor device, the method comprising the steps of: forming a plurality of transistors overlying a substrate; forming a barrier layer overlying the plurality of transistors; forming ferroelectric capacitors overlying the barrier layer; forming a plurality of contact openings between the ferroelectric capacitors and the plurality of transistors; and electrically coupling the ferroelectric capacitors to the plurality of transistors using a conductive layer comprising tantalum nitride and aluminum.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein the step of forming a barrier layer comprises: forming the barrier layer as a silicon nitride layer.
Claim 4
Dependent Claim
59 words
The method of claim 1 further comprising: exposing the plurality of transistors to a hydrogen/nitrogen anneal at a temperature which is elevated above room temperature before the step of forming the barrier layer, the hydrogen/nitrogen anneal improving yield of the plurality of transistors while the barrier layer protects the ferroelectric capacitors which are subsequently formed over the barrier layer.
Claim 5
Dependent Claim
89 words
The method of claim 3 wherein the step of electrically coupling the ferroelectric capacitors comprises: forming the tantalum nitride as: (1) a portion of a conductive interconnect connected to a capacitor electrode of the ferroelectric capacitors; and (2) an additional hydrogen or nitrogen barrier layer in addition to said barrier layer wherein the additional hydrogen or nitrogen barrier layer lies within the plurality of contact openings and aid said barrier layer in protecting the ferroelectric capacitors from one or more of nitrogen or hydrogen used in the hydrogen/nitrogen anneal.
Claim 6
Independent Claim
45 words
The method of claim further comprising: exposing the ferroelectric capacitors to an oxygen anneal at a temperature which is elevated above room temperature, the oxygen anneal improving yield of the ferroelectric capacitors while the barrier layer protects the plurality of transistors from the oxygen anneal.
Claim 7
Dependent Claim
40 words
The method of claim 1 wherein the step of forming ferroelectric capacitors comprises: forming the ferroelectric capacitor with at least one capacitor plate that contains platinum wherein the tantalum nitride is a barrier layer between the platinum and the aluminum.
Claim 8
Dependent Claim
30 words
The method of claim 1 wherein the step of electrically coupling the ferroelectric capacitors comprises: forming the conductive layer comprising all of tantalum, tantalum nitride, and a non-refractory conductive metal.
Claim 9
Dependent Claim
30 words
The method of claim 1 wherein the step of electrically coupling the ferroelectric capacitors comprises: forming the conductive layer comprising all of titanium, tantalum nitride, and a non-refractory conductive metal.
Claim 10
Independent Claim
66 words
A method for forming a ferroelectric device, the method comprising the steps of: forming a ferroelectric capacitor; forming a dielectric layer over the ferroelectric capacitor; defining at least one open in the dielectric layer to expose at least one portion of the ferroelectric capacitor; forming a barrier layer comprising tantalum nitride within the at least one opening; and forming a metallic material over the barrier layer.
Claim 11
Independent Claim
66 words
A method for forming a ferroelectric device, the method comprising the steps of: forming a ferroelectric capacitor; forming a dielectric layer over the ferroelectric capacitor; defining at least one open in the dielectric layer to expose at least one portion of the ferroelectric capacitor; forming a barrier layer comprising tantalum nitride within the at least one opening; and forming a metallic material over the barrier layer.
Claim 12
Dependent Claim
24 words
The method of claim 9 wherein the step of forming a metallic material comprises: forming the metallic material from a material which comprises aluminum.
Claim 13
Dependent Claim
33 words
The method of claim 9 wherein the step of forming a barrier layer comprises: forming the barrier layer by depositing a first layer of tantalum followed by a second layer of tantalum nitride.
Claim 14
Dependent Claim
33 words
The method of claim 9 wherein the step of forming a barrier layer comprises: forming the barrier layer by depositing a first layer of titanium followed by a second layer of tantalum nitride.
Claim 15
Dependent Claim
37 words
The method of claim 9 wherein the step of defining at least one opening comprises: defining the at least one opening to expose a platinum material portion as the at least one portion of the ferroelectric capacitor.
Claim 16
Dependent Claim
57 words
The method of claim 9 further comprising: forming at least one transistor before forming the ferroelectric capacitor; annealing the at least one transistor in an environment which contains hydrogen; and depositing a nitride layer over the at least one transistor and before forming the ferroelectric capacitor to contain the hydrogen from damaging access to the ferroelectric capacitor.
Claim 17
Dependent Claim
29 words
The method of claim 14 further comprising: annealing the ferroelectric capacitor in an ambient comprising oxygen whereby the nitride layer protects the at least one transistor from the oxygen.
Claim 18
Independent Claim
167 words
A method for forming a ferroelectric device comprising the steps of: forming a plurality of CMOS transistors over a surface of a substrate; annealing the CMOS transistors via a hydrogen anneal within a temperature range of 200° C. to 500° C.; forming a nitrogen-containing barrier layer over the CMOS transistors after the step of annealing; forming ferroelectric capacitors over the nitrogen-containing barrier, the ferroelectric capacitors each having electrodes that contain refractory metal and ferroelectric material located between the electrodes; forming at least one opening to at least one electrode of each ferroelectric capacitor; forming a conductive barrier layer within the openings, the conductive barrier layer comprising a refractory metal; forming a non-refractory metal over the conductive barrier layer and within the openings; annealing the ferroelectric material using an oxygen anneal at a temperature within a range of 300° C. to 500° C. wherein the nitrogen-containing barrier protects the CMOS transistors from the oxygen anneal and protects the ferroelectric capacitors from hydrogen previously used in the hydrogen anneal.
Claim 19
Independent Claim
167 words
A method for forming a ferroelectric device comprising the steps of: forming a plurality of CMOS transistors over a surface of a substrate; annealing the CMOS transistors via a hydrogen anneal within a temperature range of 200° C. to 500° C.; forming a nitrogen-containing barrier layer over the CMOS transistors after the step of annealing; forming ferroelectric capacitors over the nitrogen-containing barrier, the ferroelectric capacitors each having electrodes that contain refractory metal and ferroelectric material located between the electrodes; forming at least one opening to at least one electrode of each ferroelectric capacitor; forming a conductive barrier layer within the openings, the conductive barrier layer comprising a refractory metal; forming a non-refractory metal over the conductive barrier layer and within the openings; annealing the ferroelectric material using an oxygen anneal at a temperature within a range of 300° C. to 500° C. wherein the nitrogen-containing barrier protects the CMOS transistors from the oxygen anneal and protects the ferroelectric capacitors from hydrogen previously used in the hydrogen anneal.
Claim 20
Dependent Claim
37 words
The method of claim 16 wherein the step of forming the nitrogen-containing barrier layer comprises: forming the nitrogen-containing barrier layer on a top active surface of the substrate and on a backside inactive surface of the substrate.
Claim 21
Dependent Claim
29 words
The method of claim 16 wherein the step of forming the conductive barrier layer comprises: forming the conductive barrier layer so that the conductive barrier layer comprises tantalum nitride.
Claim 22
Dependent Claim
48 words
The method of claim 16 wherein the step of annealing the CMOS transistors comprises: annealing the CMOS transistors using a hydrogen anneal which also contain nitrogen in addition to hydrogen wherein the nitrogen content in the hydrogen anneal is greater than the hydrogen content in the hydrogen anneal.
Claim 23
Dependent Claim
30 words
The method of claim 16 wherein the step of forming the non-refractory metal comprises: forming the non-refractory metal comprising aluminum while forming the at least one capacitor electrode comprising platinum.
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