Fabrication method of vertical light-emitting diode
A fabrication method of a vertical light-emitting diode, such as an infrared light-emitting diode, includes heating the reaction chamber during growth of the reflective layer to pre-diffuse the metal molecules of the reflective layer into the epitaxial layer. As a result, the diffusion of the metal molecules in the reflective layer into the epitaxial layer during high-temperature fusion of the reflective layer and the epitaxial layer slows down, and the blackness level of conventional ohm contact holes is reduced.
1. A fabrication method of a vertical light-emitting diode, comprising steps of:
1) providing a first substrate, and growing a first semiconductor layer, an active layer and a second semiconductor layer thereon;
2) growing a transparent insulating layer on the second semiconductor layer surface, and etching a plurality of through-holes on the transparent insulating layer;
3) growing a metal reflective layer that covers the transparent insulating layer and the plurality of through-holes, which is heated at a heating temperature T1 during growth process, wherein, 130° C.<T1<170° C. and wherein, the metal reflective layer is AuZn or AuBe;
4) performing a high-temperature fusion of the second semiconductor layer and the metal reflective layer at a fusion temperature T2, wherein 450° C.<T2<520° C.;
5) providing a second substrate, and growing a bonding layer thereon;
6) bonding the bonding layer and the metal reflective layer, wherein the metal reflective layer is directly between the transparent insulating layer and the bonding layer; and removing the first substrate; and
7) fabricating a first electrode on the first semiconductor layer surface, and fabricating a second electrode on the second substrate surface;
wherein,
through heating at the heating temperature T1 in Step 3), metal molecules in the metal reflective layer pre-diffuse from the through-holes to the second semiconductor layer to form a mixed interface, thus reducing the diffusion level of metal molecules from the metal reflective layer to the second semiconductor layer during the high-temperature fusion in Step 4).
2. The fabrication method of claim 1 , wherein, the heating temperature T1 is 150° C.
3. The fabrication method of claim 1 , wherein, the second semiconductor layer is doped with carbon.
4. The fabrication method of claim 3 , wherein, the carbon doping concentration of the second semiconductor layer is C, wherein 3E18≤C≤1E20.
5. The fabrication method of claim 4 , wherein, the doping concentration C is 5E18.
6. The fabrication method of claim 1 , wherein, the metal reflective layer is AuZn.
7. The fabrication method of claim 1 , wherein, the growth process of the metal reflective layer in Step 3) includes thermal evaporation, electron beam evaporation, ion sputtering or any of their combinations.
8. The fabrication method of claim 1 , wherein, a fusion time of the high-temperature fusion in Step 4) is 10 minutes.
9. The fabrication method of claim 8 , wherein, the fusion temperature T2 is 480° C.
10. The fabrication method of claim 1 , wherein the vertical light-emitting diode is an infrared light-emitting diode.
11. A vertical light-emitting diode, comprising:
a first semiconductor layer;
an active layer;
a second semiconductor layer;
a transparent insulating layer with a plurality of through-holes;
a metal reflective layer that covers the transparent insulating layer and through-holes;
a bonding layer;
a second substrate;
a first electrode; and
a second electrode;
wherein, the vertical light-emitting diode is fabricated with the method according to claim 1 .
12. The vertical light-emitting diode of claim 11 , wherein, the heating temperature T1 is 150° C.
13. The vertical light-emitting diode of claim 11 , wherein, the second semiconductor layer is doped with carbon.
14. The vertical light-emitting diode of claim 13 , wherein, the carbon doping concentration of the second semiconductor layer is C, wherein 3E18<C<1E20.
15. The vertical light-emitting diode of claim 14 , wherein, the doping concentration C is 5E18.
16. The vertical light-emitting diode of claim 11 , wherein, the metal reflective layer is AuZn.
17. The vertical light-emitting diode of claim 11 , wherein, the growth process of the metal reflective layer in Step 3) includes thermal evaporation, electron beam evaporation, ion sputtering or any of their combinations.
18. The vertical light-emitting diode of claim 11 , wherein, a fusion time of the high-temperature fusion in Step 4) is 10 minutes.
19. The vertical light-emitting diode of claim 18 , wherein, the fusion temperature T2 is 480° C.
20. The vertical light-emitting diode of claim 11 , wherein the vertical light-emitting diode is an infrared light-emitting diode.