Wafer bonding of light emitting diode layers
DC CAFCFirst Claim
1. A method of forming a light emitting diode (LED) comprising:
- selecting a first material having properties compatible with fabricating LED layers having desired mechanical characteristics;
providing a first substrate made of the selected first material;
fabricating the LED layers on the first substrate, thereby forming an LED structure;
selecting an optically transparent material compatible with enhancing light-emitting performance of the LED structure; and
wafer bonding a transparent layer of the selected optically transparent material to the LED layers.
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Abstract
A method of forming a light emitting diode (LED) includes providing a temporary growth substrate that is selected for compatibility with fabricating LED layers having desired mechanical characteristics. For example, lattice matching is an important consideration. LED layers are then grown on the temporary growth substrate. High crystal quality is thereby achieved, whereafter the temporary growth substrate can be removed. A second substrate is bonded to the LED layers utilizing a wafer bonding technique. The second substrate is selected for optical properties, rather than mechanical properties. Preferably, the second substrate is optically transparent and electrically conductive and the wafer bonding technique is carried out to achieve a low resistance interface between the second substrate and the LED layers. Wafer bonding can also be carried out to provide passivation or light-reflection or to define current flow.
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Citations
29 Claims
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1. A method of forming a light emitting diode (LED) comprising:
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selecting a first material having properties compatible with fabricating LED layers having desired mechanical characteristics; providing a first substrate made of the selected first material; fabricating the LED layers on the first substrate, thereby forming an LED structure; selecting an optically transparent material compatible with enhancing light-emitting performance of the LED structure; and wafer bonding a transparent layer of the selected optically transparent material to the LED layers. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of forming a light emitting diode (LED) comprising:
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providing a temporary growth substrate having a lattice compatible with epitaxially growing LED layers; epitaxially growing a lamination of LED layers on the growth substrate, the lamination having a first side and having a second side coupled to the growth substrate, the growth substrate thereby forming a growth support surface; and substituting the temporary support surface with a permanent substrate having at least one of a higher electrical conductivity and an increased optical transparency relative to the growth substrate, the substituting including wafer bonding the permanent substrate to one of the first and second sides of the LED layers, the wafer bonding including elevating the temperature at the interface of the permanent substrate and the LED layers the wafer bonding further including applying force to compress the permanent substrate and the LED layers together to achieve a low resistance connection therebetween. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of forming a light emitting diode (LED) comprising:
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providing a first substrate; epitaxially growing a plurality of layers, including active p-n junction layers for generating light in response to the conduction of current, the layers including at least one aluminum-bearing semiconductor layer; and wafer bonding an optically transparent and electrically conductive passivation layer onto the aluminum-bearing semiconductor layer, thereby retarding the occurrence of hydrolysis within the aluminum-bearing semiconductor layer. - View Dependent Claims (15)
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16. A method of forming a light emitting diode (LED) comprising:
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providing a temporary growth substrate, including selecting the growth substrate to be compatible with lattice matching for the fabrication of LED layers; growing the LED layers on the growth substrate, the LED layers having a first side and having a second side joined to the growth substrate; and wafer bonding an electrically conductive mirror to one of the first and second sides of the LED layers to reflect light emitted in the direction of the mirror, including elevating the temperature of the LED layers and the mirror during the wafer bonding such that a low resistance connection is achieved. - View Dependent Claims (17, 18)
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19. A method of stacking light emitting diodes (LEDs) comprising:
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epitaxially growing first LED layers to form a first LED structure; epitaxially growing second LED layers to form a second LED structure; stacking the first LED structure onto the second LED structure, thereby providing an interface between the first and second LED structures; and forming an electrical connection between the first and second LED Structures at the interface, including wafer bonding the first LED structure to the second LED structure. - View Dependent Claims (20, 21, 22)
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23. A method of forming a light emitting diode (LED) having a plurality of layers including adjacent first and second layers joined at an interface, the method comprising the steps of:
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patterning a first surface of the first layer such that at least one of the optical and electrical properties will selectively vary along the interface of the first and second layers; and wafer bonding the first surface of the first layer to the second layer. - View Dependent Claims (24, 25, 26, 27, 28)
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29. A method of forming a light emitting diode (LED) comprising:
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providing a first substrate; providing a II-VI LED structure on the first substrate; and wafer bonding one of a III-V semiconductor substrate and a SiC substrate to the II-VI LED structure, thereby enhancing stability of the II-VI LED structure.
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Specification