Semiconductor light emitting device including cap structure and method of making same
A light emitting device and method of forming the same, the light emitting device including: a substrate, a buffer layer disposed on the substrate, a semiconductor mesa disposed on the buffer layer and including a first semiconductor layer, a light emitting active layer disposed on the first semiconductor layer, and a second semiconductor layer disposed on the first semiconductor layer, a contact layer disposed on an upper surface of the mesa, a passivation layer covering sidewalls of the mesa and the contact layer, and a cap structure including a reflective layer covering an upper surface of the contact layer, and a solder layer including a recess in which the reflective layer is disposed.
1. A light emitting device comprising:
a substrate;
a buffer layer disposed on the substrate;
a semiconductor mesa disposed on the buffer layer and comprising a first semiconductor layer, a light emitting active layer disposed on the first semiconductor layer, and a second semiconductor layer disposed on the first semiconductor layer;
a contact layer disposed on an upper surface of the mesa;
a passivation layer covering sidewalls of the mesa and the contact layer; and
a cap structure comprising a reflective layer covering an upper surface of the contact layer, and a solder layer comprising a recess in which the reflective layer is disposed.
2. The device of claim 1 , wherein the cap structure further comprises an adhesion layer disposed between the contact layer and the reflective layer.
3. The device of claim 2 , wherein the adhesion layer comprises Ni, Ti, Pt, TiW, or Cr.
4. The device of claim 2 , wherein the adhesion layer has a thickness ranging from about 10 angstroms to about 5000 angstroms.
5. The device of claim 1 , wherein the cap structure further comprises an adhesion layer disposed between the reflective layer and the solder layer.
6. The device of claim 5 , wherein the adhesion layer comprises Ni, Ti, Pt, TiW, or Cr.
7. The device of claim 5 , wherein the adhesion layer has a thickness ranging from about 10 angstroms to about 5000 angstroms.
8. The device of claim 1 , wherein the cap structure further comprises a wetting layer disposed between the reflective layer and the solder layer.
9. The device of claim 8 , wherein the wetting layer comprises Ni, TiW, Pt, Au, Ag, or Cr.
10. The device of claim 1 , wherein the solder layer comprises Sn, SnAu, SnAg, SnCu, SnAgCu, SnIn, SnNi, or SnAuNi.
11. The device of claim 1 , wherein the reflective layer and the solder layer cover sidewalls of the second semiconductor layer and the active layer.
12. The device of claim 1 , wherein the passivation layer is disposed between the reflective layer and the sidewalls of the second semiconductor layer and the active layer.
13. The device of claim 1 , wherein the reflective layer comprises Al, Ag, Au, or any combination thereof.
14. The device of claim 13 , wherein the reflective layer has a thickness ranging from about 500 angstroms to about 5000 angstroms.
15. The device of claim 1 , wherein the cap structure comprises:
a first adhesion layer disposed between the contact layer and the reflective layer;
a second adhesion layer disposed between the reflective layer and the solder layer; and
a wetting layer disposed between the second adhesion layer and the solder layer.
16. The device of claim 1 , wherein the device comprises a recess at least partially defined by sidewalls of the first semiconductor layer and a lower surface of the cap structure.
17. The device of claim 1 , wherein the passivation layer covers edges of the upper surface of the contact layer.