Light emitting diode containing oxidized metal contacts
A light emitting diode includes a first conductivity type semiconductor material region, an active region located over the first conductivity type semiconductor material region, a second conductivity type semiconductor material layer located over the active region, a first layer containing at least one of nickel or gold located over the second conductivity type semiconductor material layer, a reflective top contact electrode located over the first layer, a dielectric material layer located over the top contact electrode and containing an opening, and a reflector located over the dielectric material layer and contacting the top contact electrode through the opening in the dielectric material layer.
1. A light emitting diode (LED), comprising:
a first conductivity type semiconductor material region;
an active region located over the first conductivity type semiconductor material region;
a second conductivity type semiconductor material layer located over the active region;
a first layer comprising at least one of nickel or gold located over the second conductivity type semiconductor material layer;
a reflective top contact electrode located over the first layer;
a dielectric material layer located over the top contact electrode, wherein the dielectric material layer contains an opening; and
a reflector located over the dielectric material layer and contacting the top contact electrode through the opening in the dielectric material layer,
wherein:
the first conductivity type semiconductor material region, the active region and the second conductivity type semiconductor material layer are patterned into a mesa having sidewalls;
the dielectric material layer is located over the reflective top contact electrode and on sidewalls of the mesa;
the opening is located over the top of the mesa; and
the reflector is located on the dielectric material layer over the top and the sidewalls of the mesa.
2. The LED of claim 1 , wherein:
the first layer and the top contact electrode are located only on top of the mesa.
3. The LED of claim 2 , wherein the top contact electrode comprises aluminum, and the reflector comprises aluminum.
4. The LED of claim 2 , wherein a lateral width of the top contact electrode is not less than 1 microns smaller than the lateral width of the mesa.
5. The LED of claim 4 , wherein the lateral width of the top contact electrode is not less than 1 microns smaller than a lateral width of the second conductivity type semiconductor material layer in the mesa.
6. The LED of claim 5 , wherein the lateral width of the top contact electrode is the same as the lateral width of the mesa and is the same as the lateral width of the second conductivity type semiconductor material layer.
7. The LED of claim 5 , wherein the lateral width of the top contact electrode is smaller than the lateral width of the mesa by 1 micron or less.
8. The LED of claim 7 , wherein the lateral width of the top contact electrode is smaller than the lateral width of the mesa by 0.1 to 0.5 microns.
9. The LED of claim 7 , wherein the lateral width of the top contact electrode is smaller than the lateral width of the second conductivity type semiconductor material layer by 1 micron or less.
10. The LED of claim 9 , wherein the lateral width of the top contact electrode is smaller than the lateral width of the second conductivity type semiconductor material layer by 0.1 to 0.5 microns.
11. The LED of claim 2 , wherein a thickness of at least one semiconductor material layer is at least 2 microns below a portion of the reflector located past the sidewalls of the mesa.
12. The LED of claim 11 , wherein the at least one semiconductor material layer comprises a single crystalline buffer semiconductor layer.
13. The LED of claim 1 , further comprising a bonding pad and a tin portion located on the reflector.
14. The LED of claim 13 , wherein the LED is located in a direct view display device.
15. The LED of claim 14 , wherein the tin portion is bonded to a backplane of the direct view display device.
16. The LED claim 1 , wherein the first layer comprises at least one of an underlying nickel oxide layer and an overlying gold layer, a composite of nickel oxide and gold or a composite of nickel oxide and gold in which a concentration of the nickel oxide increases from bottom toward top of the transparent conductive layer.
17. The LED claim 1 , wherein the dielectric material layer comprises aluminum oxide.
18. The LED of claim 1 , wherein:
the first conductivity type semiconductor material region comprises n-type gallium nitride;
the active region comprises indium gallium nitride; and
the second conductivity type semiconductor material layer comprises p-type gallium nitride.
19. The LED of claim 1 , wherein the first conductivity type semiconductor material region comprises at least one of a semiconductor nanowire core, a semiconductor nanodisc, a semiconductor microdisc or a semiconductor layer.
20. The LED of claim 1 , wherein the reflector contacts a side surface of the dielectric material layer in the opening in the dielectric material layer.