Light-emitting diode with textured substrate
View Patent ↗A light-emitting diode (LED) device is provided. The LED device has raised semiconductor regions formed on a substrate. LED structures are formed over the raised semiconductor regions such that bottom contact layers and active layers of the LED device are conformal layers. The top contact layer has a planar surface. In an embodiment, the top contact layers are continuous over a plurality of the raised semiconductor regions while the bottom contact layers and the active layers are discontinuous between adjacent raised semiconductor regions.
1. An apparatus, comprising:
a substrate;
a patterned dielectric mask layer disposed over the substrate, wherein the patterned dielectric mask layer defines a plurality of openings;
a plurality of raised regions disposed over the substrate and within the openings, wherein the raised regions each have a non-planar upper surface;
a plurality of III-N compound components that are each disposed over the non-planar upper surface of a respective one of the raised regions, wherein the III-N compound components each have a first type of conductivity;
a plurality of multiple-quantum well (MQW) components that are each disposed over a respective one of the III-N compound components; and
a III-N compound layer disposed over the MQW components and over the patterned dielectric mask layer, wherein the III-N compound layer has a second type of conductivity different from the first type.
2. The apparatus of claim 1 , wherein: the substrate has a (100) surface orientation; and the raised regions disposed within the openings each have a (111) surface orientation.
3. The apparatus of claim 1 , wherein the non-planar upper surface is shaped as a pyramid or as a trapezoid.
4. The apparatus of claim 1 , wherein: the plurality of the III-N compounds and the plurality of the MQW components each have a non-planar upper surface; and the III-N compound layer is a continuous layer and has a planar upper surface.
5. An apparatus, comprising:
a substrate;
a mask layer over the substrate, wherein the mask layer includes a plurality of openings;
a plurality of raised regions disposed over the substrate, wherein the raised regions are each disposed within a respective one of the openings in a manner such that they prevent the substrate from being exposed;
a first contact layer including a plurality of components that are each disposed over a respective one of the raised regions, wherein the first contact layer has a first type of conductivity;
a light-emitting active layer including a plurality of components that are each disposed over a respective one of the components of the first contact layer; and
a second contact layer disposed over the light-emitting active layer and over the mask layer, wherein the second contact layer has a second type of conductivity different from the first type.
6. The apparatus of claim 5 , wherein:
the substrate has a (100) surface orientation; and
the raised regions each have a (111) surface orientation.
7. The apparatus of claim 5 , wherein the mask layer contains a dielectric material.
8. The apparatus of claim 5 , wherein the raised regions each have a pyramidal shape or a trapezoidal shape.
9. The apparatus of claim 5 , wherein:
the first contact layer and the second contact layer each contain a respective group III-N compound; and
the light-emitting active layer contains multiple quantum wells (MQW).
10. The apparatus of claim 5 , wherein the components of the first contact layer and the components of the light-emitting active layer each have a non-planar surface.
11. The apparatus of claim 5 , wherein the second contact layer is a continuous layer and has a planar surface.
12. The apparatus of claim 5 , wherein the components of the first contact layer and the components of the light-emitting active layer each are conformal to an upper surface of a respective one of the raised regions.
13. An apparatus, comprising:
a substrate;
a raised region over the substrate and providing a first surface that is non-planar;
a first contact layer over the first surface, wherein the first contact layer has a first type of conductivity;
a light-emitting active layer over the first contact layer; and
a second contact layer over the light-emitting active layer, wherein the second contact layer has a second type of conductivity different from the first type, and the second contact layer has a non-planar surface adjacent the light-emitting active layer and a planar surface opposite the non-planar surface.
14. The apparatus of claim 13 , further comprising a dielectric layer over the substrate and surrounding the raised region.
15. The apparatus of claim 13 , wherein the substrate includes silicon and the raised region includes silicon.
16. The apparatus of claim 13 , wherein the substrate has a (100) surface orientation and the raised region has a (111) surface orientation.
17. The apparatus of claim 13 , wherein the first surface is shaped as a pyramid or as a trapezoid.
18. The apparatus of claim 13 , wherein the first contact layer and the second contact layer each contain a respective group III-N compound.
19. The apparatus of claim 13 , wherein the light-emitting active layer contains multiple quantum wells (MQW).
20. The apparatus of claim 13 , wherein the first contact layer and the light-emitting active layer each are conformal to the first surface.