Ultrathin platinum films

Patent metadata

Field	Value
Publication number	US-9343749-B2
Application number	US-201313904439-A
Country	US
Kind code	B2
Filing date	May 29, 2013
Priority date	May 29, 2013
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

In at least one embodiment, a method of forming a platinum thin film is provided, including performing a first atomic layer deposition (ALD) process on a substrate using a first platinum organometallic precursor in a first step and an oxidizing precursor in a second step to form an at least partially coated substrate. A second ALD process is then performed on the at least partially coated substrate using a second platinum organometallic precursor in a first step and a reducing precursor in a second step to form a thin film of platinum on the substrate. The first ALD process may be performed for 5 to 150 cycles to nucleate platinum on the substrate surface and the second ALD process may be performed thereafter to grow the thin film and remove surface oxides. A conformal platinum thin film having a thickness of 1 to 10 monolayers may be deposited.

First claim

What is claimed is:

1. A method of forming a platinum thin film comprising:
performing a first atomic layer deposition (ALD) process on a substrate using a first platinum organometallic precursor in a first step and an oxidizing precursor in a second step, the first ALD process excluding a reducing precursor;
repeating the first ALD process for a plurality of cycles, the plurality of cycles of the first ALD process at least partially coating the substrate with metallic platinum;
performing a second ALD process on the at least partially coated substrate using a second platinum organometallic precursor in a first step and a reducing precursor in a second step, the second ALD process excluding an oxidizing precursor; and
repeating the second ALD process for a plurality of cycles, the plurality of cycles of the second ALD process forming a thin film of metallic platinum on the substrate.

2. The method of claim 1 , wherein the oxidizing precursor in the first ALD process is an oxygen plasma.

3. The method of claim 1 , wherein the reducing precursor in the second ALD process is a hydrogen plasma.

4. The method of claim 1 , wherein the substrate includes a plurality of particles.

5. The method of claim 4 , further comprising disposing the plurality of particles in a fluidized bed during the first and second performing steps.

6. The method of claim 1 , wherein the substrate is a metal oxide.

7. The method of claim 1 , wherein the substrate is a plurality of particles of one or more of yttria-stabilized zirconia (YSZ), Nb 2 O 5 , niobium doped titanium oxide, iridium oxide, and rhodium oxide.

8. The method of claim 1 , wherein the first ALD process is performed for 10 to 100 cycles.

9. The method of claim 1 , wherein a surface of the substrate has a surface contour and the second ALD process forms a platinum thin film that conforms to the surface contour and has a thickness of 1 to 10 monolayers.

10. The method of claim 1 , wherein the first and second platinum organometallic precursors are the same.

11. The method of claim 10 , wherein the first and second platinum organometallic precursors are trimethyl(methylcyclopentadienyl)platinum.

12. A method comprising:
a) depositing a first platinum organometallic precursor on a substrate surface;
b) applying only an oxygen plasma to the first precursor;
repeating steps a)-b) thereby forming a metallic platinum coating on the substrate;
c) depositing a second platinum organometallic precursor on the metallic platinum coating and the substrate;
d) applying only a hydrogen plasma to the second precursor;
repeating steps c)-d), thereby forming a metallic platinum catalyst thin film on the substrate.

13. The method of claim 12 , wherein steps a)-b) are repeated for 25 to 75 cycles.

14. The method of claim 12 , wherein steps c)-d) are repeated for 10 to 3,000 cycles.

15. The method of claim 12 , wherein the substrate is a plurality of particles and the method further comprises mixing the particles, after the hydrogen plasma is applied, with a cation-conducting polymer and a solvent to form a catalyst mixture; and
applying the catalyst mixture to one of a fuel cell electrode and a separator to form a catalyst layer, once dried.

Assignees

• Ford Global Tech Llc

Inventors

• Pietrasz Patrick
• Yang Jun

Classifications

• C23C16/45553

  characterized by the use of precursors specially adapted for ALD · CPC title

• C23C16/45555

  applied in non-semiconductor technology · CPC title

• C23C16/45536

  Use of plasma, radiation or electromagnetic fields · CPC title

• C23C16/0272

  Deposition of sub-layers, e.g. to promote the adhesion of the main coating · CPC title

• H01M4/8803

  Supports for the deposition of the catalytic active composition (H01M4/90 takes precedence) · CPC title