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 micrometer scale light emitting diode (uLED) comprising:
a plurality of continuous epitaxial layers comprising:
a n-layer having a first flat region, a sloped region, and a second flat region;
an active layer adjacent to the first flat region of the n-layer and a portion of the sloped region of the n-layer;
a p-layer adjacent to the first flat region of the active-layer and a portion of the sloped region of the n-layer;
a thickness of the n-layer in sloped region being less than a thickness of the n-layer in the first flat region or the second flat region or both; and
the active layer, or the p-layer, or both the active and p-layers comprise a pinch-off zone within the sloped region;
a p-contact on the p-layer adjacent to the first flat region; and
an n-contact on the n-layer adjacent to the second flat region.
2. The uLED of claim 1 in an absence of a passivation layer on the sloped region.
3. The uLED of claim 1 , wherein:
the thickness of the n-layer in the sloped region is less than 80% of the thickness of the n-layer in the first flat region or the second flat region or both;
a thickness of the active layer adjacent to the portion of the sloped region of the n-layer is less than 80% of the thickness of the active layer adjacent to the first flat region of the n-layer; and/or
a thickness of the p-layer adjacent to the portion of the sloped region of the n-layer is less than 80% of the thickness of the p-layer on the first flat region of the n-layer.
4. The uLED of claim 1 , wherein an angle created by the first flat region and the sloped region is between 45 degrees and 160 degrees.
5. The uLED of claim 1 , wherein the first flat region is vertically displaced from the second flat region by a distance between 1 μm and 10 μm.
6. The uLED of claim 1 further comprising at least one layer of light converting phosphor adjacent to the n-layer.
7. The uLED of claim 1 having at least one characteristic dimension of less than 100 micrometers, the character dimension being selected from the group consisting of: height, width, depth, thickness, and combinations thereof.
8. The uLED of claim 1 further comprising a body on which the plurality of continuous epitaxial layers is deposited.
9. The uLED of claim 8 , wherein the body is a substrate comprising: sapphire, silicon, silicon carbide, GaN, or GaAs.
10. A method of creating pinch-off of a region of a micrometer scale light emitting diode (uLED) comprising:
epitaxially forming a continuous n-layer having a first flat region, a sloped region, and a second flat region,
epitaxially forming a continuous active layer adjacent to a portion of the n-layer,
epitaxially forming a continuous p-layer adjacent to a portion of active layer,
a thickness of the n-layer in sloped region being less than a thickness of the n-layer in the first flat region or the second flat region or both;
the active layer, or the p-layer, or both the active and p-layers comprise a pinch-off zone within the sloped region; and
excluding passivation.
11. The method of claim 10 , wherein the uLED has at least one characteristic dimension of less than 100 micrometers, the character dimension being selected from the group consisting of: height, width, depth, thickness, and combinations thereof.
12. A micrometer scale light emitting diode (uLED) comprising:
a substrate comprising: a first flat region, a second flat region parallel to the first flat region, a sloped sidewall connecting the first flat region and the second flat region;
a plurality of continuous epitaxial layers on the substrate comprising:
a n-layer on the entirety of the substrate;
an active layer adjacent to a portion of the n-layer;
a p-layer adjacent to a portion of the active layer;
a thickness of the n-layer on the sloped sidewall being less than a thickness of the n-layer on the first flat region or the second flat region or both; and
the active layer, or the p-layer, or both the active and p-layers comprise a pinch-off zone within the sloped region;
a p-contact on the p-layer adjacent to the first flat region; and
an n-contact formed on the n-layer adjacent to the second flat region.
13. The uLED of claim 12 in an absence of a passivation layer on the sloped sidewall.
14. The uLED of claim 12 , wherein:
the thickness of the n-layer on the sloped sidewall is less than 80% of the thickness of the n-layer on the first flat region or the second flat region or both;
a thickness of the active layer adjacent to the n-layer adjacent to the sloped sidewall is less than 80% of the thickness of the active layer adjacent to the n-layer adjacent to the first flat region; and/or
a thickness of the p-layer adjacent to the n-layer adjacent to the sloped sidewall is less than 80% of the thickness of the p-layer adjacent to the n-layer adjacent to the first flat region.
15. The uLED of claim 12 , wherein an angle created by the first flat region and the sloped sidewall is between 45 degrees and 160 degrees.
16. The uLED of claim 12 , wherein the first flat region is vertically displaced from the second flat region by a distance of between 1 μm and 10 μm.
17. The uLED of claim 12 having at least one characteristic dimension of less than 100 micrometers, the character dimension being selected from the group consisting of: height, width, depth, thickness, and combinations thereof.
18. The uLED of claim 12 , wherein the substrate comprises: sapphire, silicon, silicon carbide, GaN, or GaAs.
19. A method of creating pinch-off of a region of a micrometer scale light emitting diode (uLED) comprising:
epitaxially forming a continuous n-layer on a substrate having a first flat region, a sloped sidewall, and a second flat region,
epitaxially forming a continuous active layer adjacent to a portion of the n-layer,
epitaxially forming a continuous p-layer adjacent to a portion of the n-layer,
a thickness of the n-layer adjacent to the sloped sidewall being less than a thickness of the n-layer in the first flat region or the second flat region or both;
the active layer, or the p-layer, or both the active and p-layers comprise a pinch-off zone adjacent to the sloped sidewall; and
excluding passivation.
20. The method of claim 19 , wherein the uLED has a at least one characteristic dimension of less than 100 micrometers, the character dimension being selected from the group consisting of: height, width, depth, thickness, and combinations thereof.