Deposition of LiCoO 2

• US 8,636,876 B2
• Filed: 12/07/2005
• Issued: 01/28/2014
• Est. Priority Date: 12/08/2004
• Status: Active Grant

• Current Assignee: Demaray LLC
• Original Assignee: Demaray R. Ernest
• Inventors: Zhang, Hongmei, Demaray, Richard E.
• Primary Examiner(s): MCDONALD, RODNEY GLENN
• Application Number:
  US11/297,057
• Publication Number:
  US 20060134522A1
• Time in Patent Office: 2,974 Days
• Field of Search: 204/192.12, 204/192.15, 204/192.22, 204/192.17
• US Class Current: 204/192.15
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/35 by application of a magnetic field, e.g. magnetron sputtering C23C14/3457 takes precedence
• CPC Class Codes: C23C 14/5806 Thermal treatment
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0562 Solid materials
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 2300/002 Inorganic electrolyte
• CPC Class Codes: H01M 2300/0071 Oxides
• CPC Class Codes: H01M 4/0423 Physical vapour deposition
• CPC Class Codes: H01M 4/0426 Sputtering
• CPC Class Codes: H01M 4/0428 Chemical vapour deposition
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/1391 of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/66 Selection of materials
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H01M 4/667 in the form of layers, e.g. coatings
• CPC Class Codes: H01M 6/185 with oxides, hydroxides or oxysalts as solid electrolytes
• CPC Class Codes: H01M 6/188 : Processes of manufacture
• CPC Class Codes: H01M 6/46 : of flat cells
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49115 : including coating or impregnating

Abstract

In accordance with the present invention, deposition of LiCoO₂ layers in a pulsed-dc physical vapor deposition process is presented. Such a deposition can provide a low-temperature, high deposition rate deposition of a crystalline layer of LiCoO₂ with a desired <101> or <003> orientation. Some embodiments of the deposition address the need for high rate deposition of LiCoO₂ films, which can be utilized as the cathode layer in a solid state rechargeable Li battery. Embodiments of the process according to the present invention can eliminate the high temperature (>700° C.) anneal step that is conventionally needed to crystallize the LiCoO₂ layer.

Claims

1. A method of depositing a LiCoO₂ layer, comprising:

placing a substrate in a reactor;

flowing a gaseous mixture including argon and oxygen through the reactor;

applying pulsed DC power to a densified conductive ceramic LiCoO₂ sputter target having a resistivity of about 3 kΩ

-10 kΩ

, the densified conductive ceramic LiCoO₂ sputter target being positioned opposite the substrate, wherein the conductive ceramic LiCoO₂ sputter target comprises Li and Co oxides, Li and Co metallic additions, and at least one dopant of Ni, Si, or Nb;

applying an RF bias power to the substrate; and

filtering the RF bias power with a narrow-band rejection filter from coupling into the pulsed DC power,

wherein a crystalline layer of LiCoO₂ having a columnar structure is deposited over the substrate.

2. The method of claim 1, wherein the crystalline layer is <

101>

oriented.

3. The method of claim 1, wherein the crystalline layer is <

003>

oriented.

4. The method of claim 1, wherein a grain size of the crystalline layer is between about 750 Å

and about 1700 Å

.

5. The method of claim 1 wherein the substrate is a material chosen from a set comprised of silicon, polymers, glasses, ceramics, and metals.

6. The method of claim 1, further including preheating the substrate to a temperature of about 200°

C.

7. The method of claim 1, wherein the substrate is a low temperature substrate.

8. The method of claim 7, wherein the low temperature substrate is one of a set of substrates including glass, plastic, and metal foil.

9. The method of claim 1, further including forming an oxide layer on the substrate.

10. The method of claim 9, wherein the oxide layer is a silicon dioxide layer.

11. The method of claim 2, wherein the crystalline layer is deposited at a rate of greater than about 1 μ

m per hour.

12. The method of claim 1, further including depositing a metal layer on the substrate.

13. The method of claim 12, wherein the metal layer is iridium.

14. The method of claim 1, further including annealing the crystalline layer with a low thermal budget.

15. The method of claim 12, further including annealing the LiCoO₂ layer at a temperature of less than or equal to about 500°

C.

16. The method of claim 12, further including annealing the LiCoO₂ layer at a temperature of less than or equal to about 400°

C.

17. The method of claim 1, wherein the thickness uniformity of the crystalline layer of LiCoO₂ has a standard deviation of 3% one-sigma.