Method of forming thin film using atomic layer deposition method

• US 6,576,053 B1
• Filed: 10/06/2000
• Issued: 06/10/2003
• Est. Priority Date: 10/06/1999
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Yeong-kwan, Lee, Sang-in, Choi, Sung-je, Lim, Jae-soon, Park, Young-wook
• Primary Examiner(s): HITESHEW, FELISA CARLA
• Application Number:
  US09/679,559
• Time in Patent Office: 977 Days
• Field of Search: 117/84, 117/89, 117/93, 117/95, 117/102
• US Class Current: 117/89
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/20 Aluminium oxides
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• 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 21/02186 the material containing titanium, e.g. TiO2
• 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 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/02197 the material having a perovskite structure, e.g. BaTiO3
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/316 composed of oxides or glassy oxides or oxide based glass
• CPC Class Codes: H01L 21/31691 with perovskite structure

Abstract

In a method of forming a thin film using an atomic layer deposition (ALD) method, a thin film is formed on a substrate in cycles. Each cycle includes injecting a first reactant including an atom that forms the thin film and a ligand into a reaction chamber that includes the substrate, purging the first reactant, injecting a second reactant into the reaction chamber, and purging the second reactant. The thin film is formed by a chemical reaction between the atom that forms the thin film and a second reactant whose binding energy with respect to the atom that forms the thin film is larger than the binding energy of the ligand with respect to the atom that forms the thin film and the generation of by-products is prevented. The generation of a hydroxide by-product in the thin film is suppressed by using a material that does not include a hydroxide as the second reactant, purging the second reactant, and reacting the second reactant with a third reactant that includes hydroxide. After purging the second reactant, the third reactant for removing impurities and improving the stoichiometry of the thin film is injected and purged. In this way, it is possible to obtain a thin film that does not include impurities and whose stoichiometry is excellent.

Claims

1. A method of forming a thin film over a substrate using atomic layer deposition (ALD), comprising:

placing the substrate into a reaction chamber;

injecting a first reactant into the reaction chamber so that a portion of the first reactant is chemisorbed onto the substrate, the first reactant including a thin film atom and a ligand;

purging the reaction chamber with a first inert gas to remove any of the first reactant that is only physisorbed onto the substrate;

injecting a second reactant into the reaction chamber to form the thin film in atomic layers by a chemical reaction between the thin film atom and the second reactant, and to remove the ligand without generating by-products; and

purging the reaction chamber with a second inert gas, after injecting the second reactant, to remove any of the second reactant that is physisorbed onto the substrate,

wherein the binding energy of the second reactant with respect to the thin film atom is larger than the binding energy of the ligand with respect to the thin film atom.

2. A method of forming a thin film, as recited in claim 1, wherein the first reactant comprises Al(CH₃)₃ and the second reactant comprises an activated oxidizing agent.

3. A method of forming a thin film, as recited in claim 1, wherein the first and second inert gases are the same.

4. A method of forming a thin film, as recited in claim 1, wherein the injecting of the first reactant into the reaction chamber, the purging of the reaction chamber with a first inert gas, the injecting of the second reactant into the reaction chamber, and the purging of the reaction chamber with a second inert gas, are repeated a plurality of times.

5. A method of forming a thin film using an ALD method, comprising:

placing a substrate into a reaction chamber;

injecting a first reactant into the reaction chamber so that a portion of the first reactant is chemically adsorbed onto the substrate;

purging the reaction chamber with a first inert gas to remove any first reactant that is only physisorbed over the substrate;

injecting a second reactant into the reaction chamber to chemically exchange a first portion of the chemisorbed first reactant and to form a metal-oxygen atomic layer film;

purging the reaction chamber with a second inert gas to remove any of the second reactant that is physisorbed over the substrate; and

injecting a third reactant into the reaction chamber to form a metal oxide film in units of atomic layers by chemically exchanging a second portion of the chemisorbed first reactant,

wherein the second reactant does not contain a hydroxide.

6. A method of forming a thin film, as recited in claim 5, wherein the injecting of the third reactant into the reaction chamber operates to prevent the generation of hydroxide.

7. A method of forming a thin film, as recited in claim 5, wherein the first reactant is a metal reactant, the second reactant is N₂O, O₂, O₃, or CO₂, and the third reactant is an oxidizing gas.

8. A method of forming a thin film, as recited in claim 5, wherein the temperature of the reaction chamber is maintained to be between 100 and 400°

C. from the injecting the first reactant to the injecting the third reactant.

9. A method of forming a thin film, as recited in claim 5, wherein the metal oxide film comprises a material selected from the group consisting of an Al₂O₃ film, a TiO₂ film, a ZrO₂ film, an HfO₂ film, a Ta₂O₅ film, an Nb₂O₅ film, a CeO₂ film, a Y₂O₃ film, an SiO₂ film, an In₂O₃ film, an RuO₂ film, an IrO₂ film, an SrTiO₃ film, a PbTiO₃ film, an SrRuO₃ film, a CaRuO₃ film, a (Ba,Sr)TiO₃ film, a Pb(Zr,Ti)O₃ film, a (Pb,La)(Zr,Ti)O₃ film, an (Sr,Ca)RuO₃ film, a (Ba,Sr)RuO₃ film, an In₂O₃(ITO) film doped with Sn, and an I₂O₃ film doped with Zr.

10. A method of forming a thin film, as recited in claim 5,

wherein a dangling bond on a surface of the substrate is terminated by injecting an oxidizing gas into the reaction chamber before injecting the first reactant, and

wherein the substrate is a silicon substrate.

11. A method of forming a thin film, as recited in claim 5, further comprising purging the reaction chamber with a third inert gas after injecting the third reactant into the reaction chamber, to remove any of the third reactant physisorbed over the substrate.

12. A method of forming a thin film, as recited in claim 11, wherein the first, second, and third inert gases are the same.

13. A method of forming a thin film, as recited in claim 11, wherein the injecting of the first reactant into the reaction chamber, the purging of the reaction chamber with the first inert gas, the injecting of the second reactant into the reaction chamber, the purging of the reaction chamber with the second inert gas, the injecting of the third reactant into the reaction chamber, and the purging of the reaction chamber with the third inert gas, are repeated a plurality of times.

14. A method of forming a thin film, as recited in claim 11, further comprising injecting a fourth reactant into the reaction chamber, after purging of the reaction chamber with the third inert gas, to remove any impurities and to improve the stoichiometry of the metal oxide film.

15. A method of forming a thin film, as recited in claim 14, wherein the fourth reactant is ozone gas.

16. A method of forming a thin film, as recited in claim 11, wherein the first, second, and third inert gases are the same.

17. A method of forming a thin film, as recited in claim 16, wherein the from the injecting of the first reactant into the reaction chamber, the purging of the reaction chamber with the first purge gas, the injecting of the second reactant into the reaction chamber, the purging of the reaction chamber with the second purge gas, the injecting of the third reactant into the reaction chamber, the purging of the reaction chamber with the third purge gas, are repeated a plurality of times.

18. A method of forming a thin film using an ALD method, comprising:

loading a substrate into a reaction chamber;

injecting a first reactant into the reaction chamber so that a portion of the first reactant is chemically adsorbed into the substrate;

purging the reaction chamber with a first inert gas to remove any of the first reactant that is only physisorbed over the substrate;

injecting a second reactant into the reaction chamber to form the thin film in units of atomic layers by chemically exchanging the first reactant to further contribute to the formation of the second reactant;

purging the reaction chamber with a second inert gas to remove any of the second reactant that is physisorbed over the substrate; and

injecting a third reactant into the reaction chamber to remove impurities and improving the stoichiometry of the thin film.

19. A method of forming a thin film, as recited in claim 18, wherein the first reactant comprises a metal reactant and the second and third reactants comprise oxidizing gases.

20. A method of forming a thin film, as recited in claim 18, wherein the thin film comprises a metal oxide film formed of a single atomic oxide or a composite oxide.

21. A method of forming a thin film, as recited in claim 20, wherein the single atomic oxide comprises a material selected from the group consisting of Al₂O₃, TiO₂, Ta₂O₅, ZrO₂, HfO₂, Nb₂O_{5, CeO2}, Y₂O₃, SiO₂, In₂O₃, RuO₂, and IrO₂.

22. A method of forming a thin film, as recited in claim 20, wherein the composite oxide comprises a material selected from the group consisting of SrTiO₃, PbTiO₃, SrRuO₃, CaRuO₃, (Ba,Sr)TiO₃, Pb(Zr,Ti)O₃, (Pb,La) (Zr,Ti)O₃, (Sr,Ca)RuO₃, In₂O₃ doped with Sn, In₂O₃ doped with Fe, and In₂O₃ doped with Zr.

23. A method of forming a thin film, as recited in claim 18, wherein the first reactant is a metal reactant and the second and third reactants are nitriding gases.

24. A method of forming a thin film, as recited in claim 18, wherein the thin film comprises a metal nitride film formed of a single atomic nitride or a composite nitride.

25. A method of forming a thin film, as recited in claim 24, wherein the single atomic nitride comprises a material selected from the group consisting of SiN, NbN, ZrN, TiN, TaN, Ya₃N₅, AIN, GaN, WN, and BN.

26. A method of forming a thin film, as recited in claim 24, wherein the composite nitride comprises a material selected from the group consisting of WBN, WSiN, TiSiN, TaSiN, AlSiN, and AlTiN.

27. A method of forming a thin film, as recited in claim 18, further comprising purging the reaction chamber with a third inert gas, after injecting the third reactant, to remove any of the third reactant that is physisorbed over the substrate.

28. A method of forming a thin film, as recited in claim 18,

wherein a dangling bond on a surface of the substrate is terminated by injecting oxidizing gas or nitriding gas into the reaction chamber before injecting the first reactant, and

wherein the substrate is a silicon substrate.

29. A method of forming a thin film, as recited in claim 18, wherein the temperature of the reaction chamber is maintained to be between 100 and 400°

C. from the injecting of the first reactant to the injecting of the third reactant.

30. A method of forming a thin film over a substrate using atomic layer deposition (ALD), comprising:

placing the substrate into a reaction chamber;

injecting a first reactant into the reaction chamber so that a portion of the first reactant is chemisorbed onto the substrate, the first reactant including a thin film atom and a ligand;

purging the reaction chamber with a first inert gas to remove any of the first reactant that is only physisorbed onto the substrate; and

injecting a second reactant, comprising an activated oxidizing agent, into the reaction chamber to form the thin film in atomic layers by a chemical reaction between the thin film atom and the second reactant, and to remove the ligand without generating by-products,

wherein the activated oxidizing agent comprises O₃ and the binding energy of the second reactant with respect to the thin film atom is larger than the binding energy of the ligand with respect to the thin film atom.

31. A method of forming a thin film over a substrate using atomic layer deposition (ALD), comprising:

placing the substrate into a reaction chamber;

injecting a first reactant into the reaction chamber so that a portion of the first reactant is chemisorbed onto the substrate, the first reactant including a thin film atom and a ligand;

purging the reaction chamber with a first inert gas to remove any of the first reactant that is only physisorbed onto the substrate;

injecting a second reactant into the reaction chamber to form the thin film in atomic layers by a chemical reaction between the thin film atom and the second reactant, and to remove the ligand without generating by-products; and

purging the reaction chamber with a second inert gas, after injecting the second reactant, to remove any of the second reactant that is physisorbed onto the substrate,

wherein the binding energy of the second reactant with respect to the thin film atom is larger than the binding energy of the ligand with respect to the thin film atom,

wherein the first reactant comprises Al(CH₃)₃ and the second reactant comprises an activated oxidizing agent, and

wherein the activated oxidizing agent comprises a material selected from the group consisting of O₃, O₂ plasma, and N₂O plasma.

32. A method of forming a thin film over a substrate using atomic layer deposition (ALD), comprising:

placing the substrate into a reaction chamber;

injecting a first reactant, comprising Al(CH₃)₃, into the reaction chamber so that a portion of the first reactant is chemisorbed onto the substrate, the first reactant including a thin film atom and a ligand;

purging the reaction chamber with a first inert gas to remove any of the first reactant that is only physisorbed onto the substrate; and

injecting a second reactant, comprising an activated oxidizing agent, into the reaction chamber to form the thin film in atomic layers by a chemical reaction between the thin film atom and the second reactant, and to remove the ligand without generating by-products,

wherein the activated oxidizing agent comprises O₃ and the binding energy of the second reactant with respect to the thin film atom is larger than the binding energy of the ligand with respect to the thin film atom.