Method and apparatus for preparing integrated circuit thin films by chemical vapor deposition

• US 6,110,531 A
• Filed: 07/14/1997
• Issued: 08/29/2000
• Est. Priority Date: 02/25/1991
• 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:
  US08/892,485
• Time in Patent Office: 1,142 Days
• Field of Search: 427/561, 427/565, 427/564, 427/562, 427/576, 427/569, 427/255.1, 427/255.2, 427/255.3, 427/422, 427/255.19, 427/255.25, 427/255.29, 427/255.31 , 427/255.32, 427/255.36, 438/778, 438/785, 438/758
• US Class Current: 427/255.25
• CPC Class Codes: B05D 1/00 Processes for applying liquids or other fluent materials B05D5/00, B05D7/00 take precedence
• 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: B05D 1/60 Deposition of organic layers from vapour phase vapour phase deposition in general C23C14/00, C23C16/00
• CPC Class Codes: B05D 3/0493 using vacuum
• CPC Class Codes: C23C 16/0218 in a reactive atmosphere C23C16/0227 takes precedence
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• 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 16/4486 by producing an aerosol and subsequent evaporation of the droplets or particles
• 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 16/4558 Perforated rings
• CPC Class Codes: C23C 16/46 characterised by the method used for heating the substrate C23C16/48, C23C16/50 take precedence
• CPC Class Codes: C23C 16/482 using incoherent light, UV to IR, e.g. lamps
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: C23C 26/02 applying molten material to the substrate
• CPC Class Codes: C23C 4/123 Spraying molten metal
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/68 : Crystals with laminate structure, e.g. "superlattices"
• CPC Class Codes: C30B 7/00 : Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions from molten solvents C30B9/00; by normal or gradient freezing C30B11/00; under a protective fluid C30B27/00
• CPC Class Codes: C30B 7/005 : Epitaxial layer growth
• CPC Class Codes: H01C 7/1013 : Thin film varistors
• CPC Class Codes: H01L 21/02197 : the material having a perovskite structure, e.g. BaTiO3
• CPC Class Codes: H01L 21/02274 : in the presence of a plasma [PECVD]
• 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 28/55 : with a dielectric comprising a perovskite structure material
• CPC Class Codes: H01L 28/56 : the dielectric comprising two or more layers, e.g. comprising buffer layers, seed layers, gradient layers
• CPC Class Codes: H01L 28/60 : Electrodes
• CPC Class Codes: H05K 3/105 : by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam
• CPC Class Codes: H10B 12/30 : DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells
• CPC Class Codes: H10B 53/00 : Ferroelectric RAM [FeRAM] devices comprising ferroelectric memory capacitors
• CPC Class Codes: H10N 30/076 : by vapour phase deposition
• CPC Class Codes: H10N 30/8536 : Alkaline earth metal based oxides, e.g. barium titanates

Abstract

A mist is generated by a venturi from liquid precursors containing compounds used in chemical vapor deposition, transported in carrier gas through tubing at ambient temperature, passed into a heated zone where the mist droplets are gasified at a temperature of between 100° C. and 200° C., which is lower than the decomposition temperature of the precursor compounds. The gasified liquid is injected through an inlet assembly into a deposition reactor in which there is a substrate heated to from 400° C. to 600° C., on which the gasified compounds decompose and form a thin film of layered superlattice compound.

Claims

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

(a) providing at least one liquid precursor;

(b) forming a mist of said at least one liquid precursor;

(c) gasifying said mist to form a gasified precursor comprising amounts of a bismuth-containing organic compound, a metal polyalkoxide compound, and a lead-containing organic compound without breaking the chemical bonds of said compounds;

(d) transporting said gasified precursor to a deposition reactor using at least one carrier gas;

(e) flowing oxygen gas into said deposition reactor;

(f) mixing said gasified precursor, said at least one carrier gas and said oxygen gas to form a reactant gas in said deposition reactor;

(g) providing a substrate in a deposition reactor; and

(h) reacting said reactant gas in said deposition reactor to form said thin film on said substrate, wherein said thin film comprises a layered superlattice material represented by a formula of;

space="preserve" listing-type="equation">(Sr.sub.a Ba.sub.b Pb.sub.c)(Nb.sub.x Ta.sub.y)Bi.sub.2 O.sub.9

where a+b+c=1, 0≦

c≦

1, x+y=2.

2. A method of fabricating an integrated circuit including a thin film of a compound containing at least two metals, said method comprising steps of:

(a) providing;

a liquid precursor suitable for forming said compound; and

a deposition reactor containing a substrate;

said liquid precursor comprising at least one metal polyalkoxide compound containing said at least two metals, said 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;

(b) forming a mist of said liquid precursor using a venturi mister;

(c) gasifying said mist to form a gasified precursor;

(d) flowing said gasified precursor into said deposition reactor;

(e) reacting said gasified precursor in said deposition reactor to form said thin film of said complex compound on said substrate; and

(f) completing said integrated circuit to include at least a portion of said thin film in an active component of said integrated circuit.

3. A method as in claim 2 wherein said step of forming a mist of said liquid precursor using a venturi mister comprises flowing a gas across an open throat of a tube containing said liquid precursor, with the flow of said gas being substantially parallel to said open throat.

4. A method as in claim 3 wherein said tube is a capillary tube.

5. A method as in claim 2 and further including a step of flowing oxygen gas into said deposition reactor prior to said step of reacting.

6. A method as in claim 2 and further including a step of mixing said gasified precursor with oxygen gas prior to said step of reacting.

7. A method as in claim 2 wherein said liquid precursor includes a metal compound including at least one of said metals, and wherein said step of gasifying comprises gasifying said liquid precursor without breaking the chemical bonds of said metal compound.

8. A method as in claim 2 wherein said compound comprises a layered superlattice material.

9. A method as in claim 2 wherein said layered superlattice material contains a superlattice generator element selected from the group consisting of bismuth, yttrium, scandium, lanthanum, antimony, chromium, and thallium.

10. A method as in claim 2 wherein said liquid precursor comprises a bismuth-containing organic compound selected from the group consisting of trimethyl bismuth (Bi(CH₃)₃), triethyl bismuth (Bi(C₂ H₇)₃), triphenyl bismuth, Bi-tertiary butoxide, Bi-tertiary pentoxide, and Bi-tertiary amyloxide.

11. A method as in claim 2 wherein said at least one metal polyalkoxide compound comprises chemical elements in proportions represented by a formula of:

space="preserve" listing-type="equation">(Sr.sub.d Ba.sub.e)((Nb.sub.p Ta.sub.q)(OR.sub.6).sub.2

where d+e=1, p+q=1, R is C₂ H₅ or CH(CH₃)₂.

12. A method as in claim 8 wherein said layered superlattice material is a material represented by a formula of:

space="preserve" listing-type="equation">(Sr.sub.a Ba.sub.b Pb.sub.c)(Nb.sub.x Ta.sub.y)Bi.sub.2 O.sub.9

where a+b+c=1, 0≦

c≦

1, x+y=2.

13. A method as in claim 2 wherein said step of gasifying comprises heating at a temperature at which said metal polyalkoxide compound does not decompose.

14. A method as in claim 13 wherein said temperature is below 300°

C.

15. A method as in claim 13 wherein said temperature is below 200°

C.

16. A method as in claim 2 further comprising at least one step of treating said thin film at temperatures of from 400°

C. to 900°

C. to crystallize said thin film in a phase including more grains with a high polarizability orientation than prior to said at least one step of treating, whereby said at least one step of treating is RTP, oxygen furnace annealing or a second anneal after an electrode or other contact to the thin film is formed.

17. A method as in claim 2 wherein said step of reacting includes a step of plasma-exciting said gasified precursor in said deposition reactor.

18. A method as in claim 2 wherein said step of reacting comprises a step of heating said substrate to a temperature between 300°

C. and 600°

C.

19. A method as in claim 2 and further including a step of prebaking said substrate prior to said step of reacting.

20. A method as in claim 2 wherein said step of completing comprises forming an electrode on said thin film.

21. A method as in claim 2 wherein said step of flowing comprises flowing said gasified precursor through a showerhead injector into said deposition reactor.

22. A method of fabricating an integrated circuit including a thin film of a compound containing at least two metals, said method comprising steps of:

(a) providing;

a liquid precursor suitable for forming said compound; and

a deposition system comprising a first chamber, a deposition chamber containing a substrate, and a showerhead separating said first chamber and said deposition chamber;

wherein said liquid precursor comprises at least one metal polyalkoxide compound containing said at least two metals, said 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;

(b) forming a mist of said liquid precursor;

(c) gasifying said mist to form a gasified precursor;

(d) flowing said gasified precursor through said showerhead into said deposition reactor;

(e) reacting said gasified precursor in said deposition reactor to form said thin film on said substrate; and

(f) completing said integrated circuit to include at least a portion of said thin film of said layered superlattice material compound in an active component of said integrated circuit.

23. A method as in claim 22 and wherein said step of gasifying takes place in said first chamber.

24. A method as in claim 22 and wherein said step of gasifying takes place outside of said first chamber and further including a step of transporting said gasified precursor to said first chamber.

25. A method as in claim 22 and further including a step of mixing said gasified precursor with oxygen.

26. A method as in claim 25 wherein said step of mixing takes place in said first chamber.

27. A method as in claim 22 wherein said step of gasifying comprises gasifying said mist without breaking the chemical bonds of said metal polyalkoxide compound.

28. A method as in claim 22 wherein said compound comprises a layered superlattice material.

29. A method as in claim 22 wherein said at least one metal polyalkoxide compound comprises chemical elements in proportions represented by a formula of:

space="preserve" listing-type="equation">(Sr.sub.d Ba.sub.e)((Nb.sub.p Ta.sub.q)(OR).sub.6).sub.2

where d+e=1, p+q=1, R is C₂ H₅ or CH(CH₃)₂.

30. A method of fabricating an integrated circuit including a thin film of a compound containing at least two metals, said method comprising steps of:

(a) providing a plurality of liquid precursors each containing a metal compound containing at least one of said two metals, wherein said at least two metals are 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;

(b) forming a mist of each of said liquid precursors;

(c) mixing said mists to create a combined mist;

(d) gasifying said combined mist to form a gasified precursor;

(e) transporting said gasified precursor to a deposition reactor using at least one carrier gas; and

(f) reacting said gasified precursor in said deposition reactor to form said thin film on said substrate; and

(i) completing said integrated circuit to include at least a portion of said thin film of said compound in an active component of said integrated circuit.

31. A method of fabricating an integrated circuit including a thin film of a compound containing at least two metals, said method comprising steps of:

(a) providing a plurality of liquid precursors suitable for forming said compound; and

a deposition reactor containing a substrate wherein said at least two metals are contained in said liquid precursors and 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;

(b) flowing said liquid precursors at controlled flow rates to a mixer;

(c) mixing said liquid precursors to form a combined liquid precursor just prior to forming a mist;

(d) forming a mist of said combined liquid precursor;

(e) gasifying said mist to form a gasified precursor;

(f) flowing said gasified precursor into said deposition reactor; and

(g) reacting said gasified precursor in said deposition reactor to form said thin film of said compound on said substrate.