Method of making light emitting diodes (LEDs) with improved light extraction by roughening
First Claim
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1. A method comprising:
- providing a light-emitting diode (LED) wafer assembly having a plurality of LED stacks disposed above a conductive substrate, each of the LED stacks comprising;
a p-doped layer disposed above the conductive substrate;
an active layer for emitting light disposed above the p-doped layer; and
an n-doped layer disposed above the active layer;
applying a protective layer covering a selected portion of a surface of the n-doped layer for each of the plurality of LED stacks;
altering the surface of the n-doped layer by at least one of roughening and texturing, wherein the protective layer shields the selected portion of each of the plurality of LED stacks during the altering;
removing the protective layer; and
forming an n-electrode above the selected portion after removing the protective layer.
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Abstract
Methods are provided for fabricating a semiconductor light-emitting diode (LED) device by providing an LED wafer assembly having an LED stack and selectively roughening and/or texturing a light-emitting surface of the LED stack'"'"'s n-doped layer. In this manner, light extraction from the LED device is improved.
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Citations
19 Claims
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1. A method comprising:
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providing a light-emitting diode (LED) wafer assembly having a plurality of LED stacks disposed above a conductive substrate, each of the LED stacks comprising; a p-doped layer disposed above the conductive substrate; an active layer for emitting light disposed above the p-doped layer; and an n-doped layer disposed above the active layer; applying a protective layer covering a selected portion of a surface of the n-doped layer for each of the plurality of LED stacks; altering the surface of the n-doped layer by at least one of roughening and texturing, wherein the protective layer shields the selected portion of each of the plurality of LED stacks during the altering; removing the protective layer; and forming an n-electrode above the selected portion after removing the protective layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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providing a light-emitting diode (LED) wafer assembly having a plurality of LED stacks disposed above a conductive substrate, each of the LED stacks comprising; a p-doped layer disposed above the conductive substrate; an active layer for emitting light disposed above the p-doped layer; and an n-doped layer disposed above the active layer; applying a protective layer covering a selected portion of a surface of the n-doped layer for each of the plurality of LED stacks; altering the surface of the n-doped layer by at least one of roughening and texturing, wherein the protective layer shields the selected portion of each of the plurality of LED stacks during the altering, wherein altering the surface of the n-doped layer comprises; immersing the surface of the n-doped layer having the protective layer applied in an electrolytic solution; applying an electrical bias to the conductive substrate; and illuminating the surface of the n-doped layer such that photoelectrochemical (PEC) oxidation and etching occurs to roughen the surface of the n-doped layer, wherein the protective layer shields the selected portion of each of the plurality of LED stacks during the illuminating; and removing the protective layer. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method comprising:
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providing a light-emitting diode (LED) wafer comprising a plurality of LED dies; selectively altering a desired portion of a light-emitting surface of each of the plurality of LED dies by at least one of roughening and texturing, wherein each of the plurality of LED dies has a remaining portion of the light-emitting surface that is excluded from the altering;
wherein altering the light-emitting surface comprises applying polystyrene spheres to the desired portion; andforming an n-electrode above the remaining portion of the light-emitting surface after the altering. - View Dependent Claims (17, 18, 19)
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Specification