Chemical vapor deposition methods of forming barium strontium titanate comprising dielectric layers, including such layers having a varied concentration of barium and strontium within the layer

• US 7,208,198 B2
• Filed: 06/28/2004
• Issued: 04/24/2007
• Est. Priority Date: 07/13/2001
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Basceri, Cem, Alzola, Nancy
• Primary Examiner(s): Meeks; Timothy
• Assistant Examiner(s): TUROCY, DAVID P
• Application Number:
  US10/876,703
• Publication Number:
  US 20040241322A1
• Time in Patent Office: 1,030 Days
• Field of Search: 427/255.15, 427/255.19, 427/126.3, 427/255.23, 427/255.31, 427/255.32, 427/255.36, 427/255.7, 427/248.1, 427/255.28, 438/3, 438/785
• US Class Current: 427/255.36
• CPC Class Codes: C23C 16/409 of the type ABO3 with A representing alkali, alkaline earth metal or lead and B representing a refractory metal, nickel, scandium or a lanthanide
• CPC Class Codes: C23C 16/45523 Pulsed gas flow or change of composition over time

Abstract

The invention includes a chemical vapor deposition method of forming a barium strontium titanate comprising dielectric layer having a varied concentration of barium and strontium, and/or titanium, within the layer. A substrate is positioned within a chemical vapor deposition reactor. Barium and strontium are provided within the reactor by flowing at least one metal organic precursor to the reactor. Titanium is provided within the reactor. One or more oxidizers are flowed to the reactor. In one aspect, conditions are provided within the reactor to be effective to deposit a barium strontium titanate comprising dielectric layer on the substrate from the reactants.

Claims

1. A chemical vapor deposition method of forming a barium strontium titanate-comprising dielectric layer having a varied concentration of barium and strontium within the layer, comprising:

providing a substrate within a chemical vapor deposition reactor;

providing barium and strontium within the reactor by flowing at least one metal organic precursor to the reactor, and providing titanium within the reactor, and flowing a constant composition oxidizer stream to the reactor, under conditions effective to deposit a barium strontium titanate-comprising dielectric layer on the substrate;

the barium and strontium being provided within the reactor during all of the deposit of said layer at a substantially constant atomic ratio of barium to strontium; and

during said deposit, changing a rate of flow of the constant composition oxidizer stream to the reactor at least once to effect a change in relative atomic concentration of barium to strontium within the deposited barium strontium titanate-comprising dielectric layer.

2. The method of claim 1 comprising changing the rate of flow at least twice.

3. The method of claim 1 comprising providing the barium and strontium within the reactor by flowing at least two metal organic precursors to the reactor, one of the precursors comprising barium, another of the precursors comprising strontium.

4. The method of claim 1 comprising providing the barium and strontium within the reactor by flowing at least two metal organic precursors to the reactor, one of the precursors comprising barium, another of the precursors comprising strontium, the one and the another precursors being fed to the reactor as a mixture in a single flow stream.

5. The method of claim 1 comprising providing the barium and strontium within the reactor during all of the deposit of said layer at substantially constant volumetric flow rates to the reactor.

6. The method of claim 1 wherein the oxidizer is inorganic.

7. The method of claim 1 wherein the oxidizer comprises NO_x, where “

x”

is at least 1.

8. The method of claim 1 wherein the oxidizer comprises NO.

9. The method of claim 1 wherein the constant composition oxidizer stream comprises multiple oxidizers.

10. A chemical vapor deposition method of forming a barium strontium titanate-comprising dielectric layer having a varied concentration of titanium within the layer, comprising:

providing a substrate within a chemical vapor deposition reactor;

providing barium and strontium within the reactor by flowing at least one metal organic precursor to the reactor, and providing titanium within the reactor, and flowing a constant composition oxidizer stream to the reactor, under conditions effective to deposit a barium strontium titanate-comprising dielectric layer on the substrate;

the barium and strontium being provided within the reactor during all of the deposit of said layer at a substantially constant atomic ratio of barium to strontium; and

during said deposit, changing a rate of flow of the constant composition oxidizer stream to the reactor at least once to effect a change in atomic concentration of titanium relative to barium and strontium within the deposited barium strontium titanate-comprising dielectric layer.

11. The method of claim 10 wherein the changing of a rate of flow of the oxidizer to the reactor at least once is also effective to effect a change in relative atomic concentration of barium to strontium within the deposited barium strontium titanate-comprising dielectric layer.

12. The method of claim 10 comprising changing the rate of flow at least twice.

13. The method of claim 10 wherein the oxidizer is inorganic.

14. The method of claim 10 wherein the oxidizer comprises NO_x, where “

x”

is at least 1.

15. The method of claim 10 wherein the oxidizer comprises NO.

16. A chemical vapor deposition method of forming a barium strontium titanate-comprising dielectric layer having a varied concentration of barium and strontium within the layer, comprising:

providing a substrate within a chemical vapor deposition reactor;

providing barium and strontium within the reactor by flowing at least one metal organic precursor to the reactor, and providing titanium within the reactor, and flowing only a single oxidizer to the reactor, under conditions effective to deposit a barium strontium titanate-comprising dielectric layer on the substrate;

the barium and strontium being provided within the reactor during all of the deposit of said layer at a substantially constant atomic ratio of barium to strontium; and

during said deposit, changing a rate of flow of the single oxidizer to the reactor at least once to effect a change in relative atomic concentration of barium to strontium within the deposited barium strontium titanate-comprising dielectric layer.

17. The method of claim 16 comprising changing the rate of flow at least twice.

18. The method of claim 16 comprising providing the barium and strontium within the reactor by flowing at least two metal organic precursors to the reactor, one of the precursors comprising barium, another of the precursors comprising strontium.

19. The method of claim 16 comprising providing the barium and strontium within the reactor by flowing at least two metal organic precursors to the reactor, one of the precursors comprising barium, another of the precursors comprising strontium, the one and the another precursors being fed to the reactor as a mixture in a single flow stream.

20. The method of claim 16 comprising providing the barium and strontium within the reactor during all of the deposit of said layer at substantially constant volumetric flow rates to the reactor.

21. The method of claim 16 wherein the oxidizer is inorganic.

22. The method of claim 16 wherein the oxidizer comprises NO_x, where “

x”

is at least 1.

23. The method of claim 16 wherein the oxidizer comprises NO.

24. A chemical vapor deposition method of forming a barium strontium titanate-comprising dielectric layer having a varied concentration of titanium within the layer, comprising:

providing a substrate within a chemical vapor deposition reactor;

providing barium and strontium within the reactor by flowing at least one metal organic precursor to the reactor, and providing titanium within the reactor, and flowing only a single oxidizer to the reactor, under conditions effective to deposit a barium strontium titanate-comprising dielectric layer on the substrate;

the barium and strontium being provided within the reactor during all of the deposit of said layer at a substantially constant atomic ratio of barium to strontium; and

during said deposit, changing a rate of flow of the single oxidizer to the reactor at least once to effect a change in atomic concentration of titanium relative to barium and strontium within the deposited barium strontium titanate-comprising dielectric layer.

25. The method of claim 24 wherein the changing of a rate of flow of the oxidizer to the reactor at least once is also effective to effect a change in relative atomic concentration of barium to strontium within the deposited barium strontium titanate-comprising dielectric layer.

26. The method of claim 24 comprising changing the rate of flow at least twice.

27. The method of claim 24 wherein the oxidizer is inorganic.

28. The method of claim 24 wherein the oxidizer comprises NO_x, where “

x”

is at least 1.

29. The method of claim 24 wherein the oxidizer comprises NO.