Methods of forming an insulating metal oxide

• US 8,541,276 B2
• Filed: 04/09/2012
• Issued: 09/24/2013
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Ahn, Kie Y., Forbes, Leonard
• Primary Examiner(s): Quach, Tuan N.
• Application Number:
  US13/442,140
• Publication Number:
  US 20120196448A1
• Time in Patent Office: 533 Days
• Field of Search: 438/763, 438/778, 438/785, 438/257, 438/261, 438/287, 257/E21.267, 257/E21.295
• US Class Current: 438/261
• CPC Class Codes: C23C 16/0281 of metallic sub-layers C23C16/029 takes precedence
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02186 the material containing titanium, e.g. TiO2
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• 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 21/02244 of a metallic layer
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/28229 by deposition of a layer, e.g. metal, metal compound or poysilicon, followed by transformation thereof into an insulating layer
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/3142 of nano-laminates, e.g. alternating layers of Al203-Hf02
• CPC Class Codes: H01L 29/513 the variation being perpendicular to the channel plane
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence

Abstract

A dielectric containing an insulating metal oxide film having multiple metal components and a method of fabricating such a dielectric produce a reliable dielectric for use in a variety of electronic devices. Embodiments include a titanium aluminum oxide film structured as one or more monolayers. Embodiments also include structures for capacitors, transistors, memory devices, and electronic systems with dielectrics containing a titanium aluminum oxide film.

Claims

1. A method comprising:

forming a dielectric containing an insulating metal oxide using a reaction sequence ALD process, the insulating metal oxide being an oxide compound containing multiple different metals and containing titanium, aluminum, and oxide, including forming the insulating metal oxide by conducting cycles of a monolayer or partial monolayer sequencing process in a multiple layer process with one or more oxygen annealings performed between the cycles of the monolayer or partial monolayer sequencing process such that a first titanium aluminum oxide layer in the multiple layer process is titanium rich and is converted to an oxide layer by one of the oxygen annealings, the annealings being different from the monolayer or partial monolayer sequencing process, a second titanium aluminum oxide layer having a stoichiometry different from being titanium rich, and a nitride layer.

2. The method of claim 1, wherein conducting cycles of the monolayer or partial monolayer sequencing process comprises conducting cycles of a self-limiting monolayer or partial monolayer sequencing process.

3. The method of claim 1, wherein the one or more oxygen annealings performed includes using atomic oxygen.

4. The method of claim 1, wherein the one or more oxygen annealings performed includes using molecular oxygen.

5. The method of claim 1, wherein forming the insulating metal oxide includes forming a bimetal oxide.

6. The method of claim 1, wherein conducting cycles of the monolayer or partial monolayer sequencing process in the multiple layer process includes first forming a layer of only one metal species of the multiple different metals, converting the layer of the only one metal species to a layer of an oxide of the metal species by one of the oxygen annealings, and further processing with the multiple different metals to form a composition of the insulating metal oxide containing multiple different metals.

7. The method of claim 1, wherein the method includes forming silicon oxide having a thickness of at most four monolayers as an interface between the dielectric and a structure on which the dielectric is disposed.

8. The method of claim 1, wherein forming the dielectric includes forming the dielectric structured substantially as the insulating metal oxide.

9. The method of claim 1, wherein forming the dielectric includes forming the dielectric structured as a nanolaminate.

10. The method of claim 1, wherein forming the dielectric structured as a nanolaminate dielectric includes forming the dielectric structured as a nanolaminate having an insulating metal oxide different from the insulating metal oxide containing the multiple different metals.

11. The method of claim 1, wherein forming the insulating metal oxide includes forming the insulating metal oxide rich in one species of the multiple different metals.

12. The method of claim 1, wherein forming the dielectric includes forming the dielectric structured in a memory device.

13. A method comprising:

forming a dielectric containing titanium aluminum oxide (TiAlOx) with a reaction sequence ALD process, including forming the titanium aluminum oxide by conducting cycles of a monolayer or partial monolayer sequencing process in a multiple layer process with one or more oxygen annealings performed between the cycles of the monolayer or partial monolayer sequencing process such that a first layer in the multiple layer process is formed of one or more of titanium or aluminum, a second layer is formed of one or more of titanium or aluminum, and a third layer is formed of nitride wherein the first layer is titanium rich and the second layer has as stoichiometry that is different from being titanium rich, at least the first and second layers converted to an oxide layer by one of the oxygen annealings, the annealings being different from the monolayer or partial monolayer sequencing process.

14. The method of claim 13, wherein conducting cycles of the monolayer or partial monolayer sequencing process in the multiple layer process includes first forming a layer of titanium without aluminum, converting the layer of the titanium to a layer of an oxide of titanium by one of the oxygen annealings, and further processing with aluminum to form a composition of the titanium aluminum oxide.

15. The method of claim 13, wherein conducting cycles of the monolayer or partial monolayer sequencing process in the multiple layer process includes first forming a first layer having only titanium and aluminum as metals in the first layer, converting the first layer to a layer of an oxide of titanium and aluminum by one or more of the oxygen annealings, and further processing with aluminum and titanium using the monolayer or partial monolayer sequencing process to form a composition of the titanium aluminum oxide.

16. The method of claim 13, wherein forming the dielectric includes forming an insulating metal oxide different from the titanium aluminum oxide.

17. The method of claim 16, wherein forming the insulating metal oxide different from the titanium aluminum oxide includes forming titanium oxide (TiO_x).

18. A method comprising:

forming a memory array having a dielectric containing titanium aluminum oxide (TiAlO_x) with a reaction sequence ALD process, including forming the titanium aluminum oxide by conducting cycles of a monolayer or partial monolayer sequencing process in a multiple layer process with one or more oxygen annealings performed between the cycles of the monolayer or partial monolayer sequencing process such that a first layer in the multiple layer process is formed of one or more of titanium or aluminum, a second layer formed of one or more of titanium or aluminum, and a third layer formed of nitride wherein the first layer is titanium rich and the second layer has as stoichiometry that is different from being titanium rich, at least the first and second layers converted to an oxide layer by one of the oxygen annealings, the annealings being different from the monolayer or partial monolayer sequencing process.

19. The method of claim 18, wherein forming the memory array structured as part of a flash memory device including forming the dielectric as nanolaminate having a titanium oxide film and a titanium aluminum oxide film.

20. The method of claim 18, wherein the method includes forming the dielectric as a gate insulator of a transistor in the memory array.

21. The method of claim 18, wherein the method includes forming the dielectric as an inter-gate insulator between and contacting a floating gate and a control gate of a transistor in the memory array.

22. The method of claim 18, wherein the method includes forming the dielectric as a capacitor dielectric of a capacitor in the memory array.

23. The method of claim 18, wherein forming the dielectric includes forming one or more of a nitride or insulating metal oxide, the insulating metal oxide different from the titanium aluminum oxide.