Three dimensional features on light emitting diodes for improved light extraction
View Patent ↗A method is disclosed for obtaining a high-resolution lenticular pattern on the surface of a light emitting diode. The method comprises imprinting a patterned sacrificial layer of etchable material that is positioned on a semiconductor surface that is in turn adjacent a light emitting active region, and thereafter etching the imprinted sacrificial layer and the underlying semiconductor to transfer an imprinted pattern into the semiconductor layer adjacent the light emitting active region.
1. An LED precursor structure comprising a substrate or submount:
at least one Group III nitride active layer on said substrate or said submount;
a photoresist layer on said Group III nitride-layer; and
an embossing stamp pressed into said photoresist layer.
2. An LED precursor according to claim 1 wherein said photoresist layer is heated to a temperature sufficient to soften the photoresist but below the temperature at which the photoresist would lose structural integrity.
3. An LED precursor according to claim 1 heated to a temperature of between about 50 and 100° C.
4. An LED precursor according to claim 1 further comprising a conductive substrate supporting said Group III nitride layer.
5. An LED comprising:
a conductive substrate;
at least one light-emitting active layer on said substrate; and
a patterned semiconductor lenticular surface on said active layer opposite said substrate with no more than 25 microns of non-lenticular material between said patterned lenticular surface and said active layer.
6. An LED according to claim 5 wherein said lenticular surface comprises a plurality of lenticular features that are smaller than 10 microns in their individual footprints.
7. An LED according to claim 5 wherein said lenticular surface comprises a plurality of substantially identical lenticular features.
8. An LED according to claim 5 wherein said lenticular surface comprises a plurality of lenticular features that are smaller than 6 microns in their individual footprints.
9. An LED according to claim 5 wherein said active layer comprises a Group III nitride.
10. An LED according to claim 9 wherein said lenticular surface comprises silicon carbide.