Epitaxial lift off stack having a unidirectionally shrunk handle and methods thereof
View Patent ↗Embodiments of the invention generally relate to epitaxial lift off (ELO) thin films and devices and methods used to form such films and devices. In one embodiment, a method for forming an ELO thin film is provided which includes depositing an epitaxial material over a sacrificial layer on a substrate, adhering a unidirectionally induced-shrinkage support handle onto the epitaxial material, and shrinking the support handle tangential to reinforcement fibers therein to form tension in the support handle and compression in the epitaxial material during the shrinking process. The unidirectionally induced-shrinkage support handle contains a shrinkable material and reinforcement fibers extending unidirectional throughout the shrinkable material. The method further includes removing the sacrificial layer during an etching process, peeling the epitaxial material from the substrate while forming an etch crevice therebetween, and bending the support handle to have substantial curvature.
1. A method for forming a thin film material for at least one of a solar device, a semiconductor device, and an electronic device 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 shrinkable material comprises a material selected from the group consisting of plastic, polymer, oligomer, derivatives thereof, and combinations thereof.
3. The method of claim 1 , wherein the reinforcement fibers are high-strength polymeric fibers.
4. 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.
5. 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.
6. 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.
7. 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.
8. 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.
9. The method of claim 1 , wherein the substrate comprises gallium arsenide, n-doped gallium arsenide, p-doped gallium arsenide, or derivatives thereof.
10. A method for forming a thin film material for at least one of a solar device, a semiconductor device, and an electronic device 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.
11. A thin film stack material for at least one of a solar device, a semiconductor device, and an electronic device, 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.
12. The thin film stack material of claim 11 , wherein the shrinkable material comprises a material selected from the group consisting of plastic, polymer, oligomer, derivatives thereof, and combinations thereof.
13. The thin film stack material of claim 11 , wherein the reinforcement fibers are high-strength polymeric fibers.
14. The thin film stack material of claim 11 , wherein the reinforcement fibers comprise a negative linear thermal expansion coefficient along the length of the fiber.
15. The thin film stack material of claim 11 , wherein the support handle comprises a heat shrink polymer and high-strength polymeric fibers.
16. The thin film stack material of claim 11 , 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.
17. The thin film stack material of claim 11 , 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.
18. The thin film stack material of claim 11 , 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.
19. The thin film stack material of claim 11 , wherein the sacrificial layer comprises a material selected from the group consisting of aluminum arsenide, alloys thereof, derivatives thereof, and combinations thereof.
20. The thin film stack material of claim 11 , wherein the substrate comprises gallium arsenide, n-doped gallium arsenide, p-doped gallium arsenide, or derivatives thereof.