High dielectric constant transition metal oxide materials

• US 7,723,767 B2
• Filed: 08/03/2006
• Issued: 05/25/2010
• 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:
  US11/499,479
• Publication Number:
  US 20060267066A1
• Time in Patent Office: 1,391 Days
• Field of Search: 438/528, 257/300, 257/E21.008, 257/E21.009, 257/E29.218, 257/E29.343, 257/E29.346
• US Class Current: 257/300
• 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 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• 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. An integrated circuit with a capacitor array comprising:

a plurality of conductive bottom electrodes;

a dielectric layer extending over each bottom electrode, wherein the dielectric layer comprises a transition metal oxide wherein the transition metal oxide comprises hafnium oxide with a non-metal dopant in a tetragonal crystal structure and has a dielectric constant substantially at least 30% higher than the transition metal oxide without the dopant; and

a conductive upper electrode overlying over each dielectric layer.

2. The integrated circuit of claim 1, wherein the conductive bottom electrodes comprise titanium nitride.

3. The integrated circuit of claim 1, wherein the dielectric constant of the dielectric layer is greater than 32.

4. The integrated circuit of claim 1, wherein the dielectric constant of the dielectric layer is greater than 35.

5. The integrated circuit of claim 1, wherein the dielectric constant of the dielectric layer is greater than 37.

6. The integrated circuit of claim 1, wherein the dielectric constant of the dielectric layer is at least 40% higher than the transition metal oxide without the dopant.

7. The integrated circuit of claim 6, wherein the dielectric constant of the dielectric layer is at least 45% higher than the transition metal oxide without the dopant.

8. The capacitor of claim 1, wherein the non-metal dopant comprises nitrogen.

9. The capacitor of claim 8, wherein the dielectric layer comprises between about 1 atomic % and 20 atomic % nitrogen.

10. An integrated circuit with a capacitor array comprising:

a plurality of conductive bottom electrodes;

a dielectric layer extending over each bottom electrode, wherein the dielectric layer comprises a transition metal oxide wherein the transition metal oxide comprises zirconium oxide with a non-metal dopant in a tetragonal crystal structure and has a dielectric constant substantially at least 30% higher than the transition metal oxide without the dopant; and

a conductive upper electrode overlying over each dielectric layer.

11. The integrated circuit of claim 10, wherein the conductive upper electrodes comprise tungsten.

12. The integrated circuit of claim 10, wherein the dielectric layer has a thickness of between about 30 Å

and 200 Å

.

13. The integrated circuit of claim 12, wherein the dielectric layer has a thickness of between about 70 Å

and 120 Å

.

14. The integrated circuit of claim 10, wherein the non-metal dopant comprises nitrogen.

15. The capacitor of claim 14, wherein the dielectric layer comprises between about 1 atomic % and 20 atomic % nitrogen.

16. A capacitor for an integrated circuit comprising

a bottom electrode over a substrate;

a dielectric layer overlying the bottom electrode, wherein the dielectric layer comprises a group IVB metal oxide comprising hafnium oxide and a non-metal dopant in a tetragonal crystal structure, wherein the dielectric layer has a dielectric constant greater than 25; and

an upper electrode extending over the dielectric layer.

18. The capacitor of claim 16, wherein the bottom electrode comprises titanium nitride.

19. The capacitor of claim 16, wherein the upper electrode comprises tungsten.

20. The capacitor of claim 16, wherein the dopant comprises nitrogen.

21. The capacitor of claim 20, wherein the dielectric layer comprises between about 1 atomic % and 20 atomic % nitrogen.

22. The capacitor of claim 16, wherein the non-metal dopant comprises nitrogen.

23. The capacitor of claim 22, wherein the dielectric layer comprises between about 1 atomic % and 20 atomic % nitrogen.

17. A capacitor for an integrated circuit comprising

a bottom electrode over a substrate;

a dielectric layer overlying the bottom electrode, wherein the dielectric layer comprises a group IVB metal oxide comprising zirconium oxide and a non-metal dopant in a tetragonal crystal structure, wherein the dielectric layer has a dielectric constant greater than 25; and

an upper electrode extending over the dielectric layer.