High dielectric constant transition metal oxide materials
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.
1. A method of forming a high dielectric constant (k) material comprising implanting nitrogen into a high dielectric constant transition metal oxide material having an initial crystal structure, wherein implanting comprises converting the initial crystal structure to a predominantly tetragonal crystal structure.
2. he method of claim 1 , wherein implanting nitrogen comprises using an energy level of between about 1.2 KeV and 1.8 KeV.
3. The method of claim 1 , wherein implanting nitrogen into the high dielectric constant oxide material comprises implanting nitrogen into a zirconium oxide layer.
4. The method of claim 1 , wherein implanting nitrogen into the high dielectric constant oxide material comprises using ion beam implantation.
5. The method of claim 1 , wherein implanting nitrogen into the high dielectric constant oxide material comprises implanting nitrogen into a hafnium oxide layer.
6. The method of claim 5 , wherein implanting nitrogen into the hafnium oxide layer comprises implanting between about 1*10 15 atoms per cm 2 and 2*10 16 atoms per cm 2 .
7. The method of claim 5 , wherein implanting nitrogen into the hafnium oxide layer comprises implanting nitrogen into a hafnium oxide layer between about 30 Å and 200 Å thick.
8. The method of claim 7 , wherein implanting nitrogen into the hafnium oxide layer comprises implanting nitrogen into a hafnium oxide layer between about 70 Å and 120 Å thick.
9. The method of claim 1 , wherein the initial crystal structure is predominantly monoclinic.
10. A method of forming a capacitor dielectric, comprising:
forming a transition metal oxide layer with a predominantly monoclinic crystal structure over a capacitor electrode;
doping the transition metal oxide layer with a non-metal to convert the predominantly monoclinic crystal structure into a predominantly. tetragonal crystal structure; and
annealing the transition metal oxide layer in an inert environment.
11. The method of claim 10 , wherein annealing the transition metal oxide layer comprises annealing in an argon environment.
12. The method of claim 10 , wherein annealing the transition metal oxide layer comprises using a temperature of between about 400° C. and 900° C.
13. The method of claim 10 , wherein annealing the transition metal oxide layer comprises using a temperature of between about 500° C. and 700° C.
14. The method of claim 10 , wherein forming the transition metal oxide layer comprises forming a hafnium oxide layer.
15. The method of claim 10 , wherein forming the transition metal oxide layer comprises forming a zirconium oxide layer.
16. The method of claim 10 , wherein doping the transition metal oxide layer comprises using a pulsed laser ablation technique.
17. The method of claim 10 , wherein doping the transition metal oxide layer comprises exposing the transition metal oxide layer to a plasma containing nitrogen.
18. The method of claim 10 , wherein doping the transition metal oxide layer comprises implanting a dopant into the transition metal oxide layer.
19. The method of claim 18 , wherein implanting the dopant into the transition metal oxide layer comprises using ion beam implantation.
20. The method of claim 18 , wherein implanting the dopant into the transition metal oxide layer comprises implanting nitrogen.
21. A method of forming a capacitor dielectric, comprising:
forming a transition metal oxide layer with a predominantly monoclinic crystal structure over a capacitor electrode; and
doping the transition metal oxide layer with a non-metal to convert the predominantly monoclinic crystal structure into a predominantly tetragonal crystal structure,
wherein forming the transition metal oxide layer comprises forming the transitional metal oxide layer with a thickness of between about 30 Å and 200 Å.
22. A method of forming a capacitor on an integrated circuit comprising
forming a first capacitor electrode;
depositing a high dielectric constant material over the first capacitor electrode;
implanting the high dielectric constant material with nitrogen to form a capacitor dielectric that comprises between about 1 atomic % and 20 atomic % nitrogen in a tetragonal crystal structure; and
forming a second capacitor electrode over the capacitor dielectric.
23. The dielectric material of claim 22 , wherein the capacitor dielectric comprises between about 3 atomic % and 10 atomic % nitrogen.
24. The method of claim 22 , further comprising annealing the dielectric layer.
25. The method of claim 22 , wherein forming a first capacitor electrode comprises depositing a titanium nitride layer.
26. The method of claim 22 , wherein forming a first capacitor electrode comprises depositing a polysilicon layer.
27. The method of claim 22 , wherein depositing the high dielectric constant material comprises depositing zirconium oxide.
28. The method of claim 22 , wherein depositing the high dielectric constant material comprises depositing hafnium oxide.
29. The method of claim 22 , wherein depositing the high dielectric constant material comprises depositing a high dielectric constant material layer with a thickness of between about 30 Å and 200 Å.
30. The method of claim 29 , wherein depositing the high dielectric constant material comprises depositing a high dielectric constant material layer with a thickness of between about 70 Å and 120 Å.