High dielectric constant transition metal oxide materials

• US 8,791,519 B2
• Filed: 05/07/2010
• Issued: 07/29/2014
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Li, Jiutao, Meng, Shuang
• Primary Examiner(s): Everhart, Caridad
• Application Number:
  US12/776,209
• Publication Number:
  US 20100213574A1
• Time in Patent Office: 1,544 Days
• Field of Search: 257/528, 257/E29.218, 257/E29.343, 257/E29.346, 257/310, 438/785, 423/594.12, 423/608
• US Class Current: 257/310
• CPC Class Codes: C04B 35/48 based on zirconium or hafnium oxides, zirconates, zircon or hafnates
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02332 into an oxide layer, e.g. changing SiO to SiON
• CPC Class Codes: H01L 21/31155 by ion implantation
• CPC Class Codes: H01L 21/3143 composed of alternated layers or of mixtures of nitrides and oxides or of oxinitrides, e.g. formation of oxinitride by oxidation of nitride layers
• CPC Class Codes: H01L 21/31691 with perovskite structure
• CPC Class Codes: H01L 28/40 Capacitors

Abstract

A transition metal oxide dielectric material is doped with a non-metal in order to enhance the electrical properties of the metal oxide. In a preferred embodiment, a transition metal oxide is deposited over a bottom electrode and implanted with a dopant. In a preferred embodiment, the metal oxide is hafnium oxide or zirconium oxide and the dopant is nitrogen. The dopant can convert the crystal structure of the hafnium oxide or zirconium oxide to a tetragonal structure and increase the dielectric constant of the metal oxide.

Claims

1. A dielectric material for an integrated circuit consisting essentially of a transition metal oxide layer with a non-metal dopant in a tetragonal crystal structure, wherein the dielectric material has a dielectric constant at least 30% higher than the transition metal oxide without the dopant, wherein the metal in the transition metal oxide consists essentially of hafnium or zirconium, wherein the dopant is nitrogen and wherein the dielectric material comprises between about 1 atomic % and 20 atomic % nitrogen.

2. The dielectric material of claim 1, wherein the transition metal oxide is hafnium oxide.

3. The dielectric material of claim 1, wherein the transition metal oxide is zirconium oxide.

4. The dielectric material of claim 1, wherein the dielectric constant is at least 45% higher than the transition metal oxide without the dopant.

5. The dielectric material of claim 1, wherein the dielectric constant is greater than 32.

6. The dielectric material of claim 1, wherein the dielectric constant is greater than 35.

7. The dielectric material of claim 1, wherein the dielectric material comprises between about 3 atomic % and 10 atomic % nitrogen.

8. The dielectric material of claim 1, wherein the dielectric constant is at least 40% higher than the transition metal oxide without the dopant.

9. The dielectric material of claim 8, wherein the dielectric constant is greater than 37.

10. The dielectric material of claim 1, wherein the dielectric material has a thickness of between about 30 Å

and 200 Å

.

11. The dielectric material of claim 10, wherein the dielectric material has a thickness of between about 70 Å

and 120 Å

.

12. A dielectric material for an integrated circuit consisting essentially of a hafnium oxide or zirconium oxide layer with a nitrogen dopant in a predominantly tetragonal crystal structure,

wherein the dielectric material has a dielectric constant at least 30% higher than the hafnium oxide or zirconium oxide without the nitrogen dopant, and

wherein the dielectric material comprises between about 1 atomic % and 20 atomic % nitrogen.

13. The dielectric material of claim 12, wherein the dielectric material comprises between about 3 atomic % and 10 atomic % nitrogen.

14. The dielectric material of claim 12, wherein the oxide is hafnium oxide.

15. The dielectric material of claim 14, wherein the dielectric material comprises between about 3 atomic % and 10 atomic % nitrogen.

16. The dielectric material of claim 12, wherein the oxide is zirconium oxide.

17. The dielectric material of claim 16, wherein the dielectric material comprises between about 3 atomic % and 10 atomic % nitrogen.