Micro light emitting devices
Techniques, devices, and systems are disclosed and include LEDs with a first flat region, at a first height from an LED base and including a plurality of epitaxial layers including a first n-layer, a first active layer, and a first p-layer. A second flat region is provided, at a second height from the LED base and parallel to the first flat region, and includes at least a second n-layer. A sloped sidewall connecting the first flat region and the second flat region is provided and includes at least a third n-layer, the first n-layer being thicker than at least a portion of third n-layer. A p-contact is formed on the first p-layer and an n-contact formed on the second n-layer.
1. A light emitting diode (LED) comprising:
a first plurality of epitaxial layers comprising:
a first n-layer having a first flat portion, a second sloped portion, a third flat portion, a fourth pinched portion, and a fifth flat portion,
a first active layer having a first flat portion adjacent to the first flat portion of the first n-layer and a second sloped portion adjacent to second sloped portion of the first n-layer;
a first p-layer having a first flat portion adjacent to the first flat portion of the first active layer and a second sloped portion adjacent to the second sloped portion of the first active layer;
wherein the first flat portion of the first p-layer is thicker than at least a part of the second sloped portion of the first p-layer;
a p-contact on the first flat portion of the first p-layer; and
an n-contact formed on the third flat portion of the first n-layer.
2. The LED of claim 1 , wherein the third flat portion of the first n-layer is thicker than at least a part of the fourth pinched portion of the first n-layer.
3. The LED of claim 1 , wherein the first plurality of epitaxial layers further comprises a first electron blocking layer located between the first p-layer and the first active layer, the first electron blocking layer having a first portion adjacent to the first flat portion and a second portion adjacent to the second sloped portion of the first p-layer.
4. The LED of claim 3 , wherein the first active layer contacts the first n-layer, the first electron blocking layer contacts the first active layer, and the first p-layer contacts the first active layer.
5. The LED of claim 1 further comprising a second plurality of epitaxial layers adjacent to the fifth flat portion of the first n-layer, the second plurality of epitaxial layers comprising: a second p-layer, and a second active layer.
6. The LED of claim 5 , wherein the second plurality of epitaxial layers further comprises a second electron blocking layer located between the second p-layer and the second active layer.
7. The LED of claim 1 further comprising at least one layer of light converting phosphor adjacent to the first n-layer.
8. The LED of claim 1 , wherein there is an absence of a passivation layer on the second sloped portion of the first n-layer.
9. The LED of claim 1 , wherein the LED is in singulated form.
10. A light emitting diode (LED) comprising:
a patterned substrate comprising:
a first flat region,
a second flat region parallel to the first flat region,
a third flat region,
a sloped sidewall connecting the first flat region and the second flat region, and
a bottom sidewall connecting the second flat region and the third flat region,
wherein the first flat region is located at a first height from the third flat region and the second flat region is located at a second height from the third flat region;
a first plurality of epitaxial layers comprising:
a first n-layer having a first portion adjacent to the first flat region, a second portion adjacent to the sloped sidewall, a third portion adjacent to the second flat region, and a fourth portion adjacent to the bottom sidewall,
a first active layer having a first portion adjacent to the first flat region of the first n-layer and a second portion adjacent to the second portion of the first n-layer,
a first p-layer having a first portion adjacent to the first flat portion of the first active layer, and a second portion adjacent to the second portion of the first active layer,
wherein the first portion of the first p-layer adjacent to the first flat region is thicker than at least a part of the second portion of the first p-layer adjacent to the sloped sidewall;
a p-contact on the first portion of the first p-layer adjacent to the first flat region;
an n-contact formed on the third portion of the first n-layer adjacent to the second flat region.
11. The LED of claim 10 , wherein the third portion of the first n-layer adjacent to the second flat region is thicker than at least a part of the fourth portion of the first n-layer adjacent to the bottom sidewall.
12. The LED of claim 10 , wherein the first plurality of epitaxial layers further comprises a first electron blocking layer located between the first p-layer and the first active layer, the first electron blocking layer having a first portion adjacent to the first flat region of the first active layer and a second portion adjacent to the section portion of the first active layer.
13. The LED of claim 10 , wherein the first n-layer contacts the patterned substrate, the first active layer contacts the first n-layer, the first electron blocking layer contacts the first active layer, and the first p-layer contacts the first active layer.
14. The LED of claim 10 further comprising a second plurality of epitaxial layers adjacent to the third flat region, the second plurality of epitaxial layers comprising: a second n-layer, a second p-layer, and a second active layer.
15. The LED of claim 14 , wherein the second plurality of epitaxial layers further comprises a second electron blocking layer located between the second p-layer and the second active layer.
16. The LED of claim 14 , wherein the second n-layer contacts the third flat region and at least a part of the bottom sidewall, the second active layer contacts the second p-layer and at least a part of the bottom sidewall, the second electron blocking layer contacts the second active layer and at least a part of the bottom sidewall, and the second p-layer contacts the second active layer and at least a part of the bottom sidewall.
17. The LED of claim 10 , wherein a difference between the first height and the second height is between 1 μm and 10 μm.
18. The LED of claim 10 , wherein an angle created by the first flat region and the sloped sidewall is between 45 degrees and 160 degrees.
19. The LED of claim 10 , wherein the patterned substrate comprises: sapphire, silicon, silicon carbide, GaN, or GaAs and/or the first n-layer comprises nGaN and the first p-layer comprises pGaN.
20. The LED of claim 10 , wherein there is an absence of a passivation layer on the sloped sidewall.
21. The LED of claim 1 , wherein the first plurality of the epitaxial layers are in a multilevel configuration comprising such that with respect to the first n-layer, the first flat portion, the third flat portion, and the fifth flat portion are at different levels of the LED.
22. The LED of claim 10 , wherein the patterned substrate is a multilevel patterned substrate such that the second height of the second flat region from the third flat region differs from the first height of the first flat region from the third flat region, and the first plurality of the epitaxial layers are in a multilevel configuration comprising such that with respect to the first n-layer, the first flat portion and the third flat portion are at different levels of the LED.