Sapphire thin film coated flexible substrate
A method to transfer a layer of harder thin film substrate onto a softer, flexible substrate. In particular, the present invention provides a method to deposit a layer of sapphire thin film on to a softer and flexible substrate e.g. PET, polymers, plastics, paper and fabrics. This combination provides the hardness of sapphire thin film to softer flexible substrates.
1. A method for transferring a sapphire (Al 2 O 3 ) coating from a first substrate to a second substrate comprising;
at least one first deposition process to deposit at least one first thin film onto at least one first substrate to form at least one first thin film coated substrate;
at least one second deposition process to deposit at least one second thin film onto the at least one first thin film coated substrate to form at least one second thin film coated substrate;
at least one third deposition process to deposit at least one catalyst onto the at least one second thin film coated substrate to form at least one catalyst coated substrate;
at least one fourth deposition process to deposit at least one sapphire (Al 2 O 3 ) thin film onto the at least one catalyst coated substrate to form at least one sapphire (Al 2 O 3 ) coated first substrate;
at least one annealing process, wherein said at least one sapphire (Al 2 O 3 ) coated first substrate is annealed under an annealing temperature ranging from 300° C. to less than a melting point of sapphire (Al 2 O 3 ) for a time to form at least one hardened sapphire (Al 2 O 3 ) thin film coated first substrate;
attaching at least one second substrate to the at least one hardened sapphire (Al 2 O 3 ) thin film coated first substrate on a surface of the at least one hardened sapphire (Al 2 O 3 ) thin film to form a bond between the at least one second substrate and the at least one hardened sapphire (Al 2 O 3 ) thin film coated first substrate;
at least one mechanical detachment process detaching the at least one hardened sapphire (Al 2 O 3 ) thin film together with the at least one second thin film from the at least one first thin film coated substrate to form at least one second thin film coated hardened sapphire (Al 2 O 3 ) thin film on said at least one second substrate; and
at least one etching process removing the at least one second thin film from the at least one second thin film coated hardened sapphire (Al 2 O 3 ) thin film on said at least one second substrate to form at least one sapphire (Al 2 O 3 ) thin film coated second substrate.
2. The method according to claim 1 , wherein said at least one first substrate and/or said second substrate comprises at least one material with a Mohs value less than that of the at least one sapphire (Al 2 O 3 ) thin film.
3. The method according to claim 1 , wherein said at least one first or second or third or fourth deposition process comprises e-beam deposition or sputtering deposition.
4. The method according to claim 1 , wherein a thickness of said at least one first substrate and/or said at least one second substrate is of one or more orders of magnitude greater than the thickness of said at least one sapphire (Al 2 O 3 ) thin film.
5. The method according to claim 1 , wherein the thickness of said at least one sapphire (Al 2 O 3 ) thin film is about 1/1000 of the thickness of said at least one first substrate and/or said at least one second substrate.
6. The method according to claim 1 , wherein said at least one sapphire (Al 2 O 3 ) thin film has the thickness between 150 nm and 600 nm.
7. The method according to claim 1 , wherein said time is no less than 30 minutes.
8. The method according to claim 1 , wherein said time is no more than 2 hours.
9. The method according to claim 1 , wherein said annealing temperature ranges between 850° C. and 1300° C.
10. The method according to claim 1 , wherein said annealing temperature ranges between 1150° C. and 1300° C.
11. The method according to claim 1 , wherein the first substrate comprises quartz, fused silica, silicon, glass, or toughened glass, and the second substrate comprises PET, polymers, plastics, paper and/or fabric wherein the second substrate is not etch-able by the at least one etching process.
12. The method according to claim 1 , wherein the bond between said at least one substrate and said at least one hardened sapphire (Al 2 O 3 ) thin film is stronger than the bonding between said at least one first thin film and said second thin film.
13. The method according to claim 1 wherein the at least one first thin film comprises chromium (Cr) or a material that forms a weaker bond between the at least one first thin film and the at least one second thin film further wherein said material for the first thin film is not etched by the at least one etching process that etches the material for the second thin film.
14. The method according to claim 1 wherein the at least one second thin film comprises silver (Ag) or a material that forms a weaker bond between the at least one first thin film and the at least one second thin film further wherein said material for the second thin film is etched by the at least one etching process.
15. The method according to claim 1 , wherein said at least one catalyst comprises a metal selected from titanium (Ti), chromium (Cr), nickel (Ni), silicon (Si), silver (Ag), gold (Au), germanium (Ge) or a metal with a higher melting point than the at least one first substrate.
16. The method according to claim 1 , wherein said at least one catalyst coated substrate comprises at least one catalyst film.
17. The method according to claim 16 , wherein said at least one catalyst film is not continuous.
18. The method according to claim 16 , wherein said at least one catalyst film has a thickness ranging between 1 nm and 15 nm.
19. The method according to claim 16 , wherein said at least one catalyst film comprises a nano-dot with a diameter ranging between 5 nm and 20 nm.