1. A method for forming a thin film material during an epitaxial lift off process, comprising:
forming an epitaxial material over a sacrificial layer on a substrate;
adhering a support handle onto the epitaxial material, wherein the support handle comprises a shrinkable material and reinforcement fibers extending unidirectional throughout the shrinkable material;
shrinking the support handle tangential to the reinforcement fibers to form tension in the support handle and compression in the epitaxial material during a shrinking process;
removing the sacrificial layer during an etching process; and
peeling the epitaxial material from the substrate while forming an etch crevice therebetween and bending the support handle to have substantial curvature.
2. The method of claim 1, wherein the support handle comprises a bottom surface and a top surface, the bottom surface is adhered to the epitaxial material, and the support handle bends towards the top surface.
3. The method of claim 1, wherein the shrinkable material comprises an amorphous material which is crystallized to undergo a net volume reduction during the shrinking process.
4. The method of claim 1, wherein the shrinkable material comprises a material selected from the group consisting of plastic, polymer, oligomer, derivatives thereof, and combinations thereof.
5. The method of claim 1, wherein the shrinkable material comprises polyester or derivatives thereof.
6. The method of claim 1, wherein the reinforcement fibers are high-strength polymeric fibers.
7. The method of claim 6, wherein the reinforcement fibers comprise polyethylene or derivatives thereof.
8. The method of claim 6, wherein the reinforcement fibers comprise a negative linear thermal expansion coefficient along the length of the fiber.
9. The method of claim 6, wherein the reinforcement fibers comprise a tensile moduli within a range from about 15 GPa to about 134 GPa.
10. The method of claim 1, wherein the support handle is heated during the shrinking process, and the support handle comprises a heat shrink polymer and high-strength polymeric fibers.
11. The method of claim 1, wherein shrinking the support handle comprises removing solvent from the shrinkable material.
12. The method of claim 1, wherein an adhesive is used to adhere the support handle onto the epitaxial material, and the adhesive is selected from the group consisting of pressure sensitive adhesive, hot melt adhesive, UV curing adhesive, natural adhesive, synthetic adhesive, derivatives thereof, and combinations thereof.
13. The method of claim 1, wherein the sacrificial layer is exposed to a wet etch solution during the etching process, the wet etch solution comprises hydrofluoric acid, a surfactant, and a buffer.
14. The method of claim 13, wherein the sacrificial layer is etched at a rate of about 5 mmhr or greater.
15. The method of claim 1, wherein the sacrificial layer is exposed to hydrogen fluoride vapor during the etching process.
16. The method of claim 1, wherein the epitaxial material comprises a material selected from the group consisting of gallium arsenide, aluminum gallium arsenide, indium gallium phosphide, alloys thereof, derivatives thereof, and combinations thereof.
17. The method of claim 16, wherein the epitaxial material comprises a layer comprising gallium arsenide and another layer comprising aluminum gallium arsenide.
18. The method of claim 16, wherein the epitaxial material comprises a gallium arsenide buffer layer, an aluminum gallium arsenide passivation layer, and a gallium arsenide active layer.
19. The method of claim 18, wherein the gallium arsenide buffer layer has a thickness within a range from about 100 nm to about 500 nm, the aluminum gallium arsenide passivation layer has a thickness within a range from about 10 nm to about 50 nm, and the gallium arsenide active layer has a thickness within a range from about 500 nm to about 2,000 nm.
20. The method of claim 18, wherein the epitaxial material further comprises a second aluminum gallium arsenide passivation layer.
21. The method of claim 1, wherein the epitaxial material comprises a cell structure containing multiple layers comprising at least one material selected from the group consisting of gallium arsenide, n-doped gallium arsenide, p-doped gallium arsenide, aluminum gallium arsenide, n-doped aluminum gallium arsenide, p-doped aluminum gallium arsenide, indium gallium phosphide, alloys thereof, derivatives thereof, and combinations thereof.
22. The method of claim 1, wherein the sacrificial layer comprises a material selected from the group consisting of aluminum arsenide, alloys thereof, derivatives thereof, and combinations thereof.
23. The method of claim 22, wherein the sacrificial layer comprises an aluminum arsenide layer having a thickness of about 20 nm or less.
24. The method of claim 1, wherein the substrate comprises gallium arsenide, n-doped gallium arsenide, p-doped gallium arsenide, or derivatives thereof.
25. A method for forming a thin film material during an epitaxial lift off process, comprising:
positioning a substrate comprising an epitaxial material disposed over a sacrificial layer on the substrate;
adhering a support handle onto the epitaxial material, wherein the support handle comprises a shrinkable material and reinforcement fibers extending unidirectional throughout the shrinkable material;
shrinking the support handle tangential to the reinforcement fibers to form tension in the support handle and compression in the epitaxial material during a shrinking process; and
removing the sacrificial layer during an etching process, wherein the etching process further comprises:
peeling the epitaxial material from the substrate;
forming an etch crevice between the epitaxial material from the substrate; and
bending the support handle to have substantial curvature.
26. A thin film stack material, comprising:
a sacrificial layer disposed on a substrate;
an epitaxial material disposed over the sacrificial layer; and
a support handle disposed over the epitaxial material, wherein the support handle comprises a shrinkable material and reinforcement fibers extending unidirectional throughout the shrinkable material, which upon being shrunk, shrinks tangential to the reinforcement fibers to form tension in the support handle and compression in the epitaxial material.
27. The thin film stack material of claim 26, wherein the shrinkable material comprises an amorphous material which is crystallized to undergo a net volume reduction during the shrinking process.
28. The thin film stack material of claim 26, wherein the shrinkable material comprises a material selected from the group consisting of plastic, polymer, oligomer, derivatives thereof, and combinations thereof.
29. The thin film stack material of claim 26, wherein the reinforcement fibers are high-strength polymeric fibers.
30. The thin film stack material of claim 26, wherein the reinforcement fibers comprise polyethylene.
31. The thin film stack material of claim 26, wherein the reinforcement fibers comprise a negative linear thermal expansion coefficient along the length of the fiber.
32. The thin film stack material of claim 26, wherein the reinforcement fibers comprise a tensile moduli within a range from about 15 GPa to about 134 GPa.
33. The thin film stack material of claim 26, wherein the support handle comprises a heat shrink polymer and high-strength polymeric fibers.
34. The thin film stack material of claim 26, wherein an adhesive is between the support handle and the epitaxial material, and the adhesive is selected from the group consisting of pressure sensitive adhesive, hot melt adhesive, UV curing adhesive, natural adhesive, synthetic adhesive, derivatives thereof, and combinations thereof.
35. The thin film stack material of claim 26, wherein the epitaxial material comprises a material selected from the group consisting of gallium arsenide, aluminum gallium arsenide, indium gallium phosphide, alloys thereof, derivatives thereof, and combinations thereof.
36. The thin film stack material of claim 35, wherein the epitaxial material comprises a layer comprising gallium arsenide and another layer comprising aluminum gallium arsenide.
37. The thin film stack material of claim 35, wherein the epitaxial material comprises a gallium arsenide buffer layer, an aluminum gallium arsenide passivation layer, and a gallium arsenide active layer.
38. The thin film stack material of claim 37, wherein the gallium arsenide buffer layer has a thickness within a range from about 100 nm to about 500 nm, the aluminum gallium arsenide passivation layer has a thickness within a range from about 10 nm to about 50 nm, and the gallium arsenide active layer has a thickness within a range from about 500 nm to about 2,000 nm.
39. The thin film stack material of claim 37, wherein the epitaxial material further comprises a second aluminum gallium arsenide passivation layer.
40. The thin film stack material of claim 26, wherein the epitaxial material comprises a cell structure containing multiple layers comprising at least one material selected from the group consisting of gallium arsenide, n-doped gallium arsenide, p-doped gallium arsenide, aluminum gallium arsenide, n-doped aluminum gallium arsenide, p-doped aluminum gallium arsenide, indium gallium phosphide, alloys thereof, derivatives thereof, and combinations thereof.
41. The thin film stack material of claim 26, wherein the sacrificial layer comprises a material selected from the group consisting of aluminum arsenide, alloys thereof, derivatives thereof, and combinations thereof.
42. The thin film stack material of claim 41, wherein the sacrificial layer comprises an aluminum arsenide layer having a thickness of about 20 nm or less.
43. The thin film stack material of claim 42, wherein the thickness is within a range from about 1 nm to about 10 nm.
44. The thin film stack material of claim 43, wherein the thickness is within a range from about 4 nm to about 6 nm.
45. The thin film stack material of claim 26, wherein the substrate comprises gallium arsenide, n-doped gallium arsenide, p-doped gallium arsenide, or derivatives thereof.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for the introduction of a polymerisation catalyst in solid form into a gas-phase fluidised bed, which process comprises using an injection device having an inner tube of internal cross-sectional area of 10 to 100 mm2 and an outer tube forming an annulus around said inner tube with a cross-sectional area of 2 to 10 times the internal cross-sectional area of the inner tube, and passing said polymerisation catalyst and a carrier gas through the inner tube and into the gas-phase fluidised bed at a linear velocity of said carrier gas of 4 to 14 ms and at a mass flow rate of carrier gas in the range of 10-35 kgh, and passing a shielding gas through the outer tube and into the gas-phase fluidised bed at a linear velocity of said shielding gas of 1 to 10 times the linear velocity of the carrier gas through the inner tube and at a mass flow rate of the shielding gas in the range 100-500 kgh, wherein no cooled recycle process gas is provided to the injection device.
2. A process according to claim 1 wherein the carrier gas is selected from olefins, inert gases and mixtures thereof.
3. A process according to claim 2 wherein the carrier gas is selected from ethylene and nitrogen.
4. A process according to claim 1 wherein the shielding gas is passed through the outer tube and into the gas-phase fluidised bed at a linear velocity of said shielding gas of 3 to 8 times the linear velocity of the carrier gas through the inner tube.
5. A process according to claim 1 wherein the cross-sectional area of the annulus is less than 500 mm2.
6. A process according to claim 1 wherein the linear velocity of the shielding gas is less than 50 ms.
7. A process according to claim 1 wherein the mass flow rate of the shielding gas is less than 400 kgh.
8. A process according to claim 1 wherein the ratio of the mass flow rate of the shielding gas to the mass flow rate of the carrier gas is less than 20.
9. A process according to claim 1 wherein the shielding gas has less than 10% inert gases by volume.
10. A process according to claim 9 wherein the shielding gas comprises less than 1% inert gases by volume.
11. A process according to claim 1 wherein the shielding gas comprises at least 90% olefins by volume.
12. A process according to claim 1 wherein the catalyst is a metallocene catalyst and the shielding gas comprises predominantly ethylene.
13. A process according to claim 12 wherein the shielding gas comprises less than 1% by volume of comonomer.
14. A process according to claim 1 wherein the catalyst is a Ziegler-Natta catalyst and the shielding gas comprises at least 1% by volume of comonomer.
15. A process according to claim 3 wherein the carrier gas is selected from nitrogen.
16. A process according to claim 5 wherein the cross-sectional area of the annulus is less than 250 mm2.
17. A process according to claim 5 wherein the cross-sectional area of the annulus is in the range 50 to 150 mm2.
18. A process according to claim 6 wherein the linear velocity of the shielding gas is 20 to 50 ms.
19. A process according to claim 7 wherein the mass flow rate of the shielding gas is in the range 100-300 kgh.
20. A process according to claim 8 wherein the ratio of the mass flow rate of the shielding gas to the mass flow rate of the carrier gas is less than 15.
21. A process according to claim 8 wherein the ratio of the mass flow rate of the shielding gas to the mass flow rate of the carrier gas is in the range 5 to 15.
22. A process according to claim 11 wherein the shielding gas comprises at least 95% olefins by volume.