Interface texturing for light-emitting device
AssigneeUnited Epitaxy Company, Ltd.
InventorsTzer-Perng Chen, Chih-Sung Chang, Holin Chang
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Abstract
The present invention discloses a light-emitting device (LED) with a textured interface formed by utilizing holographic lithography. Two coherent light beams are overlaid to cause constructive and destructive interference and thereby periodical alternative bright and dark lines are formed. A wafer coated with a photoresist material is exposed under the interference lines. After a developing step, a photoresist pattern with textured surface is formed on the wafer. Thereafter, the textured photoresist pattern is transferred to the wafer by etching process and result in a desired light-emitting device with a textured interface.
Claims6
A semiconductor epitaxial structure for a light-emitting device, comprising:
- a first window layer;
- a p-n junction active layer stacked on the first window layer;
- and
- a second window layer stacked on the p-n junction active layer, and the second window layer having a textured surface, wherein the textured surface is caused by a plurality of interference lines formed by a plurality of overlaid coherent light beams, and a method of forming the textured surface comprises:
- forming a photoresist layer on the second window layer;
- performing a first exposure process, which is to project the interference lines formed by the overlaid coherent light beams to the photoresist layer;
- rotating the photoresist layer 60 degrees;
- performing a second exposure process, which is to project the interference lines formed by the overlaid coherent light beams to the photoresist layer;
- rotating the photoresist layer 60 degrees in the same direction continuously;
- performing a third exposure process, which is to project the interference lines formed by the overlaid coherent light beams to the photoresist layer;
- performing a developing process to form a textured pattern on a surface of the photoresist layer;
- and
- performing an etching process to transfer the textured pattern of the photoresist layer to the second window layer.
Dependencies are inferred from the claim text.