Yttrium and titanium high-K dielectric film
This disclosure provides (a) methods of making an oxide layer (e.g., a dielectric layer) based on yttrium and titanium, to have a high dielectric constant and low leakage characteristic and (b) related devices and structures. An oxide layer having both yttrium and titanium may be fabricated either as an amorphous oxide or as an alternating series of monolayers. In several embodiments, the oxide is characterized by a yttrium contribution to total metal that is specifically controlled. The oxide layer can be produced as the result of a reactive process, if desired, via either a PVD process or, alternatively, via an atomic layer deposition process that employs specific precursor materials to allow for a common process temperature window for both titanium and yttrium reactions.
1. A method of forming a capacitive device, the method comprising:
creating a first conductive layer above a substrate;
depositing a dielectric above the first conductive layer,
the dielectric being deposited using a physical vapor deposition (PVD) process, the PVD process comprising reactive co-sputtering of a first source and a second source,
wherein the first source comprises metallic yttrium,
wherein the second source comprises metallic titanium,
the dielectric comprising yttrium and titanium such that a yttrium-to-total-metal constituency is between one percent and five percent; and
creating a second conductive layer above the dielectric.
2. The method of claim 1 , wherein
the physical vapor deposition process is a reactive process that fabricates an oxide comprising titanium and yttrium in situ, and
wherein the reactive co-sputtering simultaneously transfers yttrium and titanium from the first source and the second source and reacts yttrium and titanium with an oxygen-containing gas.
3. The method of claim 1 , wherein at least one of creating the first conductive layer or creating the second conductive layer comprises creating an electrode comprising one of titanium nitride (TiN), platinum, iridium, iridium oxide, tungsten, tungsten oxide, molybdenum, molybdenum oxide, ruthenium, or ruthenium oxide.
4. The method of claim 1 , further comprising fabricating a dynamic random access memory cell, the dynamic random access memory cell comprising the capacitive device.
5. The method of claim 4 , further comprising fabricating a dynamic random access memory device, the dynamic random access memory device comprising an array of dynamic random access memory cells, the array comprising the dynamic random access cell.
6. The method of claim 1 , wherein the capacitive device is one of a crown-shaped capacitor, a pillar-shaped capacitor, or a cylinder-shaped capacitor.
7. The method of claim 1 , wherein using the physical vapor deposition process comprises fabricating an amorphous oxide layer to form the dielectric.
8. The method of claim 1 , further comprising using an oxygen source subsequent to the sputtering process to form a single oxide layer.
9. The method of claim 1 , wherein the sputtering comprises reactive sputtering in an oxygen-containing gas.
10. A method of forming a capacitive device, the method comprising:
creating a first conductive layer above a substrate;
depositing a dielectric above the first conductive layer,
the dielectric being deposited using a physical vapor deposition (PVD) process, the PVD process comprising reactive co-sputtering of a first source and a second source,
wherein the first source comprises metallic yttrium,
wherein the second source comprises metallic titanium,
the dielectric comprising yttrium and titanium such that a yttrium-to-total metal constituency is between one percent and five percent,
wherein the PVD process is configured to suppress formation of crystalline titanium oxide and to suppress formation of crystalline yttrium oxide; and
creating a second conductive layer above the dielectric.
11. The method of claim 10 , wherein
the PVD process is a reactive process that fabricates an oxide comprising titanium and yttrium in situ, and
wherein the reactive co-sputtering simultaneously transfers yttrium and titanium from the first source and the second source and reacts yttrium and titanium with an oxygen-containing gas.
12. The method of claim 10 , wherein
the PVD process is a reactive process that fabricates an oxide comprising titanium and yttrium in an oxygen-rich environment.
13. The method of claim 10 , wherein at least one of creating the first conductive layer or creating the second conductive layer comprises creating an electrode comprising one of titanium nitride (TiN), platinum, iridium, iridium oxide, tungsten, tungsten oxide, molybdenum, molybdenum oxide, ruthenium, or ruthenium oxide.
14. The method of claim 10 , further comprising fabricating a dynamic random access memory cell, the dynamic random access memory cell comprising the capacitive device.
15. The method of claim 14 , further comprising fabricating a dynamic random access memory device, the dynamic random access memory device comprising an array of dynamic random access memory cells, the array comprising the dynamic random access cell.
16. The method of claim 10 , wherein the capacitive device is one of a crown-shaped capacitor, a pillar-shaped capacitor, or a cylinder-shaped capacitor.
17. A method of forming a capacitive device, the method comprising:
creating a first conductive layer above a substrate;
depositing a dielectric above the first conductive layer,
the dielectric being deposited using a physical vapor deposition (PVD) process, the PVD process comprising reactive co-sputtering of a first source and a second source,
wherein the first source comprises metallic yttrium,
wherein the second source comprises metallic titanium,
the dielectric comprising yttrium and titanium such that a yttrium-to-total-metal constituency is between one percent and five percent,
the dielectric being amorphous and having a dielectric constant of above 60; and
creating a second conductive layer above the dielectric.
18. The method of claim 17 , wherein the dielectric has leakage characteristics approximately the same as the leakage characteristics of crystalline Y 2 O 3 .
19. The method of claim 17 , wherein one of the first conductive layer or the second conductive layer comprises one of ruthenium, ruthenium oxide, platinum, a metal nitride, iridium, iridium oxide, silicon and a silicide.
20. The method of claim 17 , further comprising annealing the deposited dielectric at between 500° C. and 600° C. in an atmosphere comprising oxygen.
21. The method of claim 17 , wherein the reactive co-sputtering simultaneously transfers yttrium and titanium from the first source and the second source and reacts yttrium and titanium with an oxygen-containing gas.
22. The method of claim 17 , further comprising using an oxygen source subsequent to the sputtering process to form a single oxide layer.
23. The method of claim 22 , wherein oxygen of the oxygen source reacts with metallic yttrium sputtered from the first source and with metallic titanium sputtered from the second source to form an yttrium-titanium oxide deposed on the substrate.
24. The method of claim 17 , wherein the sputtering comprises reactive sputtering in an oxygen-containing gas.
25. The method of claim 24 , wherein oxygen of the oxygen source reacts with metallic yttrium sputtered from the first source and metallic titanium sputtered from the second source to form an yttrium-titanium oxide after the metallic yttrium is sputtered from the first source and the metallic titanium sputtered from the second source and before the metallic yttrium and the metallic titanium are deposited on the substrate.
26. The method of claim 17 , further comprising depositing a metal above the substrate, the metal being operable as an electrode.
27. The method of claim 17 , wherein a yttrium-to-total metal constituency is between one and two percent.
28. The method of claim 17 , further comprising controlling deposition of titanium and yttrium to suppress formation of crystalline titanium oxide and to suppress formation of crystalline yttrium oxide.
29. The method of claim 17 , further comprising forming a dynamic access memory cell comprising the capacitive device.