3-D structure for increasing contact surface area for LEDs
Disclosed herein is an apparatus including a first three-dimensional (3-D) structure, a second 3-D structure, and a conductive layer. The first 3D structure includes a first-type doped semiconductor material having a semi-polar facet. The second 3-D structure forms a light-emitting diode (LED) and includes a second-type doped semiconductor material, an active layer, and the first-type doped semiconductor material. The conductive layer at least partially overlays and is in ohmic contact with the semi-polar facet. The conductive layer is configured to carry current that flows between the semi-polar facet and the active layer. In some embodiments, the first-type doped semiconductor material may include an N-type doped semiconductor material, and the second-type doped semiconductor material may include a P-type doped semiconductor material. The first-type doped semiconductor material of both 3-D structures may be etched from a common first-type doped semiconductor epitaxial layer.
1. An apparatus comprising:
a first three-dimensional (3-D) structure comprising a first-type doped semiconductor material having a semi-polar facet;
a conductive layer at least partially overlaying and in ohmic contact with the semi-polar facet; and
a second 3-D structure forming a light-emitting diode (LED), wherein:
the second 3-D structure comprises a second-type doped semiconductor material, an active layer, and the first-type doped semiconductor material,
the conductive layer is configured to carry a current that flows between the semi-polar facet and the active layer,
the first 3-D structure further comprises an active layer separate from the active layer of the second 3-D structure, and
the current that flows between the semi-polar facet and the active layer of the second 3-D structure bypasses the active layer of the first 3-D structure due to a resistivity of a conductive path through the semi-polar facet being lower than that of a conductive path through the active layer of the first 3-D structure.
2. The apparatus of claim 1 , wherein the first-type doped semiconductor material of the first 3-D structure and the first-type doped semiconductor material of the second 3-D structure are etched from a common first-type doped semiconductor epitaxial layer.
3. The apparatus of claim 1 , wherein the first-type doped semiconductor material comprises an N-type doped semiconductor material, and wherein the second-type doped semiconductor material comprises a P-type doped semiconductor material.
4. The apparatus of claim 3 , wherein the N-type doped semiconductor material comprises aluminum indium gallium phosphide (AlInGaP).
5. The apparatus of claim 3 , wherein the N-type doped semiconductor material comprises a III-Nitride material.
6. The apparatus of claim 1 , wherein the first 3-D structure and the second 3-D structure have substantially similar heights.
7. The apparatus of claim 6 , wherein the first 3-D structure and the second 3-D structure have substantially similar mesa shapes.
8. The apparatus of claim 7 , wherein each of the first 3-D structure and the second 3-D structure has a parabolic shape.
9. The apparatus of claim 6 , wherein the first 3-D structure and the second 3-D structure have different shapes.
10. The apparatus of claim 9 , wherein the first 3-D structure has a rectangular plateau shape, and the second 3-D structure has a parabolic shape.
11. The apparatus of claim 1 , wherein:
the conductive layer at least partially overlays the first 3-D structure and supports an N-contact bump bond for the LED,
a second conductive layer at least partially overlays the second 3-D structure and supports a P-contact bump bond for the LED, and
the N-contact bump bond and the P-contact bump bond have similar heights with respect to a substrate on which the first 3-D structure and the second 3-D structure are formed.
12. The apparatus of claim 1 , wherein:
the first 3-D structure further comprises the second-type doped semiconductor material,
the second-type doped semiconductor material of the first 3-D structure and the second-type doped semiconductor material of the second 3-D structure are etched from a common second-type doped semiconductor epitaxial layer, and
the active layer of the first 3-D structure and the active layer of the second 3-D structure are etched from a common epitaxial layer.
13. The apparatus of claim 12 , wherein the conductive layer further overlays, at least partially, surfaces of the second-type doped semiconductor material and the active layer of the first 3-D structure.
14. The apparatus of claim 1 , wherein the first-type doped semiconductor material of the first 3-D structure further includes a C-plane facet, and wherein the conductive layer further overlays, at least partially, and is in ohmic contact with, the C-plane facet.
15. The apparatus of claim 1 , wherein the conductive layer comprises a metal.
16. The apparatus of claim 1 , wherein the conductive layer comprises a transparent conducting oxide.
17. The apparatus of claim 1 , wherein the conductive layer extends along an entire perimeter of the first 3-D structure.
18. The apparatus of claim 1 , wherein the first 3-D structure has a mesa shape, wherein the conductive layer at least partially overlays the mesa shape, and wherein a contact bump bond is formed on a top portion of the conductive layer.
19. The apparatus of claim 18 , wherein the conductive layer at least partially overlays a C-plane facet of the first 3-D structure, and wherein the conductive layer is configured to permit current to flow: through the C-plane facet and the semi-polar facet, into the conductive layer, and to the contact bump bond.
20. The apparatus of claim 19 , wherein the contact bump bond is an N-contact bump bond for the LED.