THIN FILM BATTERY DEVICE AND METHOD OF FORMATION

1 . A thin film device, comprising:

an active device region; and

a thin film encapsulant disposed adjacent to the active device region and encapsulating at least a portion of the active device region, the thin film encapsulant comprising:

an outer layer, wherein the outer layer is disposed adjacent ambient and comprises a hydrophobic layer.

2 . The thin film device of claim 1 , wherein the thin film device comprises a thin film battery, wherein the active device region comprises:

a lithium-containing cathode;

a solid state electrolyte disposed on the lithium-containing cathode; and

an anode region disposed on the solid state electrolyte, the anode region being further disposed adjacent the thin film encapsulant.

3 . The thin film device of claim 1 , wherein the thin film encapsulant comprises a plurality of layers, wherein the plurality of layers comprises at least one rigid dielectric layer and at least one polymer layer.

4 . The thin film device of claim 1 , wherein the outer layer comprises a hydrophobic material, the outer layer generating a contact angle with water of greater than 90 degrees.

5 . The thin film device of claim 4 , wherein the outer layer comprises a fluoropolymer.

6 . The thin film device of claim 1 , wherein the outer layer comprises a surface-engineered layer, wherein the surface-engineered layer comprises a non-planar outer surface.

7 . The thin film device of claim 6 , wherein the surface-engineered layer comprises a plurality of surface features, the plurality of surface features having a feature height of between one hundred nanometers and twenty micrometers.

8 . The thin film device of claim 6 , the surface-engineered layer generating a contact angle of at least 150 degrees.

9 . The thin film device of claim 6 , wherein the outer layer comprises a hydrophobic material.

10 . The thin film device of claim 1 , wherein the thin film encapsulant comprises a plurality of layers, wherein at least one inner layer of the thin film encapsulant is a non-hydrophobic layer.

11 . The thin film device of claim 1 , wherein the outer layer comprises a thickness of 1 micrometer to 20 micrometers.

12 . A thin film battery, comprising:

a lithium-containing cathode;

a solid state electrolyte disposed on the lithium-containing cathode;

an anode region disposed on the solid state electrolyte; and

a thin film encapsulant, the thin film encapsulant disposed over the anode region and comprising:

at least one polymer layer;

at least one rigid layer disposed adjacent the at least one polymer layer; and

an outer layer, wherein the outer layer is disposed adjacent ambient and comprises a hydrophobic layer.

13 . The thin film battery of claim 12 , wherein the outer layer comprises a hydrophobic material, the outer layer generating a contact angle with water of greater than 90 degrees, and wherein the at least one polymer layer and the at least one rigid layer are not hydrophobic.

14 . The thin film battery of claim 12 , wherein the outer layer comprises a surface-engineered layer, wherein the surface-engineered layer comprises a non-planar outer surface, the surface-engineered layer generating a contact angle with water of greater than 90 degrees.

15 . The thin film battery of claim 14 , wherein the surface-engineered layer comprises a plurality of surface features, the plurality of surface features having a feature height of between one hundred nanometers and twenty micrometers.

16 . A method of forming a thin film device, comprising:

forming an active device region on a substrate, the active device region comprising a water sensitive material; and

forming a thin film encapsulant on the active device region, wherein the thin film encapsulant comprises a plurality of layers, wherein an outer layer of the thin film encapsulant is disposed adjacent ambient and comprises a hydrophobic layer.

17 . The method of claim 16 , wherein the thin film device comprises a thin film battery, wherein the forming the active device region comprises:

forming a lithium-containing cathode;

forming a solid state electrolyte on the lithium-containing cathode; and

forming an anode region on the solid state electrolyte, the anode region being further disposed adjacent the thin film encapsulant.

18 . The method of claim 16 , wherein the forming the outer layer comprises patterning an outer surface of the outer layer, wherein the outer surface generates a contact angle with water of greater than 90 degrees.

19 . The method of claim 18 , wherein the patterning comprises laser micromachining the outer surface to generate a plurality of surface features, wherein the plurality of surface features comprises a feature height of between one hundred nanometers and twenty micrometers.

20 . The method of claim 16 , wherein the outer layer comprises a hydrophobic material.