Plasma resistant multi-layer architecture for high aspect ratio parts

1. An article comprising:

one or more channels; and

a multi-layer protective coating on the one or more channels, the multi-layer protective coating comprising:

an anodization layer, the anodization layer comprising a plurality of cracks and a plurality of pores;

a sealing layer on the anodization layer, wherein the sealing layer comprises a metal oxide, and wherein the sealing layer seals the plurality of cracks and the plurality of pores, the sealing layer having a porosity of approximately 0%; and

a top layer on the sealing layer, wherein the top layer comprises a metal oxide, a rare earth oxide, a rare earth fluoride, or a rare earth oxyfluoride, wherein the top layer has a same or a different material composition as compared to the sealing layer, and wherein the top layer has a porosity of approximately 0%;

wherein the multi-layer protective coating has a dielectric breakdown voltage of at least 2000 Volts.

2. The article of claim 1 , wherein the one or more channels comprise a length to diameter aspect ratio of greater than about 5:1.

3. The article of claim 1 , wherein the sealing layer consists essentially of Al 2 O 3 .

4. The article of claim 1 , wherein:

a thickness of the anodization layer is about 100 nm to about 90 microns; and

a combined thickness of the sealing layer and the top layer is about 1-5 microns.

5. The article of claim 1 , wherein the top layer comprises the metal oxide or the rare earth oxide, and wherein the rare earth oxide is selected from a group consisting of Y 2 O 3 , Al 2 O 3 , Y 3 Al 5 O 12 (YAG), Y 4 Al 2 O 9 (YAM), YAlO 3 (YAP), Er 2 O 3 , Er 3 Al 5 O 12 (EAG), ZrO 2 , Gd 2 O 3 , a solid solution of Y 2 O 3 —ZrO 2 , and a ceramic compound comprising Y 4 Al 2 O 9 and a solid-solution of Y 2 O 3 —ZrO 2 .

6. The article of claim 1 , wherein the top layer comprises the rare earth fluoride, and wherein the rare earth fluoride is selected from a group consisting of YF 3 , ErF 3 , ZrF 4 and GdF 3 .

7. The article of claim 1 , wherein the top layer comprises the rare earth oxyfluoride, and wherein the rare earth oxyfluoride is selected from a group consisting of yttrium oxyfluoride, erbium oxyfluoride, zirconium oxyfluoride, aluminum oxyfluoride, and gadolinium oxyfluoride.

8. The article of claim 1 , wherein the sealing layer is selected from a group consisting of Y 2 O 3 , Y 3 Al 5 O 12 (YAG), Y 4 Al 2 O 9 (YAM), YAlO 3 (YAP), Er 2 O 3 , Er 3 Al 5 O 12 (EAG), ZrO 2 , Gd 2 O 3 , a solid solution of Y 2 O 3 —ZrO 2 , Al 2 O 3 , and a ceramic compound comprising Y 4 Al 2 O 9 and a solid-solution of Y 2 O 3 —ZrO 2 .

9. The article of claim 1 , wherein the article comprises aluminum or an aluminum alloy, and wherein the article comprises a remote plasma delivery cylinder.

10. The article of claim 1 , wherein an electrical impedance of the multi-layer protective coating has approximately a same electrical impedance before exposure to a temperature of between about 120° C. and about 350° C. and after exposure to the temperature of between about 120° C. and about 350° C.

11. A plurality of articles, wherein:

each article of the plurality of articles comprises:

one or more channels; and

a multi-layer protective coating on the one or more channels, the multi-layer protective coating comprising:

an anodization layer, the anodization layer comprising a plurality of cracks and a plurality of pores;

a sealing layer on the anodization layer, wherein the sealing layer comprises Al 2 O 3 , and wherein the sealing layer seals the plurality of cracks and the plurality of pores, the sealing layer having a porosity of approximately 0%; and

a top layer on the sealing layer, wherein the top layer comprises a metal oxide, a rare earth oxide, a rare earth fluoride, or a rare earth oxyfluoride, wherein the top layer has a same or a different material composition as compared to the sealing layer, and wherein the top layer has a porosity of approximately 0%;

wherein a part to part variation of a dielectric breakdown voltage between the plurality of articles, as measured at the one or more channels of the plurality of articles, is less than about +/−5%.

12. The plurality of articles of claim 11 , wherein the dielectric breakdown voltage of the one or more channels for each of the plurality of articles is over 2000 Volts.

13. A method of forming a multi-layer protective coating on one or more channels of one or more articles, comprising:

anodizing a surface of the one or more channels of a first article to form an anodization layer on the one or more channels, the anodization layer comprising a plurality of cracks and a plurality of pores;

depositing a sealing layer onto the anodization layer using an atomic layer deposition (ALD) process, wherein the sealing layer comprises a metal oxide, and wherein the sealing layer seals the plurality of cracks and the plurality of pores, the sealing layer having a porosity of approximately 0%; and

depositing a top layer onto the sealing layer using the ALD process, wherein the top layer comprises a metal oxide, a rare earth oxide, a rare earth fluoride, or a rare earth oxyfluoride, wherein the top layer has a same or a different material composition as compared to the sealing layer, and wherein the top layer has a porosity of approximately 0%;

wherein the multi-layer protective coating has a dielectric breakdown voltage of at least 2000 Volts.

14. The method of claim 13 , wherein the sealing layer consists essentially of Al 2 O 3 .

15. The method of claim 13 , wherein the anodization layer has a thickness of about 0.5 microns to about 90 microns and a combined thickness of the sealing layer and the top layer is about 1-5 microns.

16. The method of claim 13 , further comprising:

anodizing surfaces of the one or more channels of a plurality of additional articles to form an anodization layer on the one or more channels of the plurality of additional articles;

depositing a sealing layer onto the anodization layer of the plurality of additional articles using the ALD process; and

depositing a top layer onto the sealing layer of the plurality of additional articles using the ALD process;

wherein a part to part variation of the dielectric breakdown voltage between the first article and the plurality of additional articles is less than about +/−5%.

17. The method of claim 13 , wherein the top layer comprises the rare earth oxide, wherein the rare earth oxide comprises a mixture of at least a first metal and a second metal, and wherein depositing the top layer comprises:

performing a deposition cycle comprising:

injecting a first precursor for the first metal into a deposition chamber containing the first article to cause the first precursor to adsorb onto a surface of the one or more channels;

subsequently injecting a second precursor for the second metal into the deposition chamber containing the first article to cause the second precursor to adsorb onto the surface of the one or more channels; and

subsequently injecting an oxygen-containing reactant into the deposition chamber; and

repeating the deposition cycle one or more times until a target thickness is reached for the top layer.

18. The method of claim 13 , wherein the top layer comprises the rare earth oxyfluoride, and wherein depositing the top layer comprises:

performing a deposition cycle comprising:

injecting a first precursor for a rare earth metal into a deposition chamber containing the first article to cause the first precursor to adsorb onto a surface of the one or more channels;

subsequently injecting a first one of an oxygen-containing reactant and a fluorine-containing reactant into the deposition chamber containing the first article; and

subsequently injecting a second one of the oxygen-containing reactant and the fluorine-containing reactant into the deposition chamber containing the first article; and

repeating the deposition cycle one or more times until a target thickness is reached for the top layer.