Method and apparatus for fabrication of thin films by chemical vapor deposition

• US 6,511,718 B1
• Filed: 12/17/1999
• Issued: 01/28/2003
• Est. Priority Date: 07/14/1997
• Status: Expired due to Fees

• Current Assignee: Symetrix Corporation
• Original Assignee: Symetrix Corporation
• Inventors: Paz de Araujo, Carlos A., Solayappan, Narayan, McMillan, Larry D., Bacon, Jeffrey W.
• Primary Examiner(s): PADGETT, MARIANNE L
• Application Number:
  US09/446,226
• Time in Patent Office: 1,138 Days
• Field of Search: 427/561, 427/562, 427/564, 427/565, 427/576, 427/529, 427/569, 427/584, 427/586, 427/255.31, 427/255.19, 427/255.29, 427/255.32, 427/255.25, 427/255.36, 427/422, 438/778, 438/785, 438/758, 438/376.2
• US Class Current: 427/576
• CPC Class Codes: B05D 1/007 using an electrostatic field B05D1/02 - B05D1/16 take precedence
• CPC Class Codes: B05D 1/04 involving the use of an electrostatic field B05D1/025 and B05D1/14 take precedence
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/448 characterised by the method used for generating reactive gas streams, e.g. by evaporation or sublimation of precursor materials
• CPC Class Codes: C23C 16/45561 Gas plumbing upstream of the reaction chamber
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 18/12 characterised by the deposition of inorganic material other than metallic material
• CPC Class Codes: H01L 21/02175 characterised by the metal H01L21/02197 takes precedence
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02183 the material containing tantalum, e.g. Ta2O5
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02192 the material containing at least one rare earth metal element, e.g. oxides of lanthanides, scandium or yttrium
• CPC Class Codes: H01L 21/02197 the material having a perovskite structure, e.g. BaTiO3
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02277 the reactions being activated by other means than plasma or thermal, e.g. photo-CVD
• CPC Class Codes: H01L 21/02356 treatment to change the morphology of the insulating layer, e.g. transformation of an amorphous layer into a crystalline layer
• CPC Class Codes: H01L 21/31691 with perovskite structure
• CPC Class Codes: H01L 28/55 : with a dielectric comprising a perovskite structure material

Abstract

A venturi mist generator creates a mist comprising droplets having a mean diameter less than one micron from liquid precursors containing multi-metal polyalkoxide compounds. The mist is mixed and then passed into a gasifier where the mist droplets are gasified at a temperature of between 100° C. and 250° C., which is lower than the temperature at which the precursor compounds decompose. The gasified precursor compounds are transported by carrier gas through insulated tubing at ambient temperature to prevent both condensation and premature decomposition. The gasified precursors are mixed with oxidant gas, and the gaseous reactant mixture is injected through a showerhead inlet into a deposition reactor in which a substrate is heated at a temperature of from 300° C. to 600 ° C. The gasified precursors decompose at the substrate and form a thin film of solid material on the substrate. The thin film is treated at elevated temperatures of from 500° C. to 900° C. to form polycrystalline metal oxide material, in particular, ferroelectric layered superlattice material.

Claims

1. A method of fabricating an integrated circuit including a thin film, comprising steps of:

providing a substrate in a deposition reactor;

providing a liquid precursor containing a metal compound;

forming a mist of said liquid precursor;

gasifying said mist to form a gasified precursor without causing substantial premature decomposition of said metal compound; and

reacting said gasified precursor and an oxidant gas in said deposition reactor to form said thin film on said substrate, said method characterized in that said mist of said liquid precursor comprises mist droplets having a mean droplet diameter less than one micron.

2. A method as in claim 1, further characterized in that said step of providing said liquid precursor comprises providing a multi-metal polyalkoxide precursor.

3. A method as in claim 1, further characterized in that said mean droplet diameter does not exceed 0.5 micron.

4. A method of fabricating an integrated circuit including a thin film, said method comprising:

providing a substrate in a deposition reactor;

providing a liquid precursor containing a metal compound;

forming a mist of said liquid precursor;

gasifying said mist to form a gasified precursor without causing substantial premature decomposition of said metal compound; and

reacting said gasified precursor and an oxidant gas in said deposition reactor to form said thin film on said substrate, said method characterized in that said thin film comprises a ferroelectric layered superlattice material;

wherein

said liquid precursor comprises at least one multi-metal polyalkoxide compound containing at least two metals selected from the group consisting of strontium, calcium, barium, cadmium, lead, tantalum, hafnium, tungsten, niobium, zirconium, bismuth, scandium, yttrium, lanthanum, antimony. chromium, molybdenum, vanadium, ruthenium and thallium and said multi-metal polyalkoxide compound includes chemical elements in proportions represented by a formula of;

5. A method as in claim 4, characterized in that said liquid precursor comprises a bismuth-containing organic compound selected from the group consisting of trimethyl bismuth (Bi(CH₃)₃), triethyl bismuth (Bi(C₂H₇)₃), triphenyl bismuth, Bi-tertiary butoxide, Bi-tertiary pentoxide, and Bi-tertiary amyloxide.

6. A method as in claim 4, characterized in that said liquid precursor comprises said metal compound dissolved in an organic solvent.

7. A method as in claim 6, characterized in that said organic solvent comprises tetrahydrofuran.

8. A method as in claim 4, characterized in that said ferroelectric layered superlattice material is a Bi-layered superlattice material.

9. A method as in claim 4, characterized in that said step of gasifying comprises heating at a temperature at which said metal compound does not substantially prematurely decompose.

10. A method as in claim 9, characterized in that said temperature is below 300°

C.

11. A method as in claim 9, characterized in that said temperature is below 200°

C.

12. A method as in claim 4, further characterized by treating said thin film at temperatures of from 500°

C. to 900°

C. to crystallize said thin film in a phase including more grains with a high polarizability orientation than prior to said treating.

13. A method as in claim 12, characterized in that said treating comprises annealing in an oxygen furnace.

14. A method as in claim 12, characterized in that said treating comprises rapid thermal processing (RTP) annealing.

15. A method as in claim 12, further characterized by performing an ion implantation step prior to said treating.

16. A method as in claim 12, characterized in that said treating comprises crystallizing said thin film in a mixed phase including both A-axis oriented grains and C-axis oriented grains.

17. A method as in claim 4, characterized by a step of plasma-exciting said gasified precursor and said oxidant gas, in said deposition reactor.

18. A method as in claim 4, characterized by irradiating said gasified precursor and said oxidant gas in said deposition reactor with ultraviolet rays.

19. A method as in claim 4, characterized by heating said substrate to a temperature between 300°

C. and 600°

C. during said reacting.

20. A method as in claim 4, characterized by a step of forming an electrode on said thin film.

21. A method as in claim 20, characterized by a step of annealing said thin film and said electrode in an oxygen furnace.

22. A method of fabricating an integrated circuit including a thin film, said method comprising:

providing a substrate in a deposition reactor;

providing a liquid precursor containing a metal compound;

forming a mist of said liquid precursor,

gasifying said mist to form a gasified precursor without causing substantial premature decomposition of said metal compound; and

reacting said gasified precursor and an oxidant gas In said deposition reactor to form said thin film on said substrate, said method characterized in that said thin film comprises a ferroelectric layered superlattice material;

said method characterized in that;

said gasified precursor contains an amount of a bismuth-containing organic compound and an amount of a metal polyalkoxide compound;

said gasified precursor comprises an amount of a lead-containing organic compound; and

said layered superlattice material comprises a ferroelectric material represented by formula of;

23. A method as in claim 22, characterized in that said amount of said bismuth-containing organic compound in said gasified precursor is between 1 and 99 weight parts and said amount of said metal polyalkoxide compound in said gasified precursor is 99 to 1 weight parts based on a combined amount of 100 weight parts of said amounts of said compounds.

24. A method as in claim 22, characterized in that said amount of said lead-containing organic compound in said gasified precursor is from 1×

10<sup>−

5</sup> to 200 weight parts when said amount of said Bi-containing organic compound and said amount of said metal polyalkoxide compound are a combined amount of 100 weight parts.

25. A method as in claim 22, characterized in that said lead-containing organic compound comprises a compound selected from the group consisting of Pb-tertiary butoxide and Pb-oxotertiary butoxide.