METAL OXIDE FILMS

• US 20080072819A1
• Filed: 09/28/2007
• Published: 03/27/2008
• Est. Priority Date: 09/11/1998
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Rahtu, Antti, Matero, Raija, Hanninen, Timo, Ritala, Mikko, Leskela, Markku, Hatanpaa, Timo, Vehkamaki, Marko
• Granted Patent: US 8,685,165 B2
• Time in Patent Office: Days
• US Class Current: 117/104
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• 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 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/32 Titanates; Germanates; Molybdates; Tungstates

Abstract

Atomic layer deposition (ALD) type processes for producing titanium containing oxide thin films comprise feeding into a reaction space vapour phase pulses of titanium alkoxide as a titanium source material and at least one oxygen source material, such as ozone, capable of forming an oxide with the titanium source material. In preferred embodiments the titanium alkoxide is titanium methoxide.

Claims

1. A deposition method for depositing a film, comprising:

providing a substrate in a reaction space; and

forming a metal oxide film on the substrate by repeatedly exposing the substrate to sequential and temporally separated pulses of an oxygen-containing material and a metal-containing material comprising a cyclopentadienyl group, wherein the pulses of the metal-containing material forms a layer of the metal on the substrate by a self-controlled surface reaction.

2. The method of claim 1, wherein the metal oxide film is a high dielectric constant film.

3. The method of claim 2, wherein the metal oxide film has a dielectric constant higher than SiO₂ and Si₃N₄.

4. The method of claim 1, wherein exposing the substrate to temporally separated pulses comprises alternatingly exposing the substrate to the pulses of the oxygen-containing material and the pulses of the metal-containing material.

5. The method of claim 1, wherein repeatedly exposing the substrate to sequential and temporally separated pulses further comprises exposing the substrate to pulses of one or more additional metal-containing materials, wherein the pulses of the additional metal-containing materials are temporally separated from pulses of other metal-containing materials or from pulses of the oxygen-containing material.

6. The method of claim 5, wherein exposing the substrate to pulses of one or more additional metal-containing materials comprises exposing the substrate to a titanium alkoxide.

7. The method of claim 1, wherein the metal-containing material is cyclopentadienyl barium or cyclopentadienyl strontium.

8. The method of claim 1, wherein the oxygen-containing material is selected from the group consisting of water, oxygen, hydrogen peroxide, aqueous solution of hydrogen peroxide, ozone, oxides of nitrogen, halide-oxygen compounds, peracids (—

O—

O—

H), alcohols, oxygen-containing radicals and mixtures thereof.

9. The method of claim 1, wherein exposing the substrate to pulses of the metal-containing material deposits the metal on the substrate by surface saturating reactions.

10. The method of claim 1, further comprising removing excess reactant from the reaction space between the pulses of the oxygen-containing material and the metal-containing material.

11. The method of claim 10, wherein removing excess reactant comprises purging the reaction space with inactive gas.

18. The method of claim 1, wherein exposing the metal-containing layer to an oxygen-containing material comprises exposing the metal-containing layer to an oxygen-containing material selected from the group consisting of water, oxygen, hydrogen peroxide, aqueous solution of hydrogen peroxide, ozone, oxides of nitrogen, halide-oxygen compounds, peracids (—

O—

O—

H), alcohols, oxygen-containing radicals and mixtures thereof.

12. An atomic layer deposition method for forming a film on a substrate, comprising;

exposing the substrate to a metal precursor to self-limitingly deposit a metal-containing layer on the substrate, the metal precursor comprising a cyclopentadienyl group; and

exposing the metal-containing layer to an oxygen-containing material to form a metal oxide film.

13. The method of claim 12, wherein exposing the substrate to the metal precursor and exposing the metal-containing layer to an oxygen-containing material constitutes a cycle, further comprising performing a plurality of cycles.

14. The method of claim 13, further comprising forming a nanolaminate film by alternating a plurality of cycles with a second plurality of cycles, each of the second plurality of cycles comprising:

exposing the substrate to a titanium alkoxide for form a titanium-containing layer on the substrate; and

exposing the titanium-containing layer to an oxygen-containing material to form titanium oxide.

15. The method of claim 14, wherein exposing the substrate to the titanium alkoxide is performed at 150-400°

C.

16. The method of claim 14, wherein the titanium alkoxide is a titanium compound comprising carbon and oxygen.

17. The method of claim 12, wherein the metal precursor is cyclopentadienyl barium or cyclopentadienyl strontium.

19. An atomic layer deposition method, comprising:

depositing a layer of material on a substrate by a self-controlled surface reaction with a surface of the substrate by exposing the substrate to a metal precursor comprising a cyclopentadienyl group; and

exposing the layer of material to an oxygen-containing material reactive with the deposited monolayer.

20. The method of claim 19, wherein the metal precursor is cyclopentadienyl barium or cyclopentadienyl strontium.

21. The method of claim 19, wherein depositing the layer and exposing the layer constitute a cycle, further comprising performing a plurality of cycles.

22. A method for growing amorphous oxide thin films on a substrate in a reactor, comprising:

producing the films by the Atomic Layer Epitaxy (ALE) process at a temperature of 150 to 400°

C. by feeding pulses of precursor compounds into the reactor alternately to achieve film growth through saturating surface reactions and by purging the reactor with an inert gas between the precursor pulses to provide alternate self-limiting surface reactions on the substrate, wherein the precursor compounds comprise;

at least one cyclopentadienyl compound containing an earth-alkali metal; and

a reactive oxygen precursor.