Gallium nitride-based light emitting device having ESD protection capacity and method for manufacturing the same
View Patent ↗A gallium nitride-based light emitting device, and a method for manufacturing the same are disclosed. The light emitting device comprises an n-type GaN-based clad layer, an active layer, a p-type GaN-based clad layer and a p-side electrode sequentially stacked on a substrate. The device further comprises an n-side electrode formed on one region of the n-type GaN-based clad layer, and two or more MIM type tunnel junctions formed on the other regions of the n-type GaN-based clad layer. Each of the MIM type tunnel junctions comprises a lower metal layer formed on the GaN-based clad layer so as to contact the n-type GaN-based clad layer, an insulating film formed on the lower metal layer, and an upper metal layer formed on the insulating film. The device is protected from reverse ESD voltage, so that tolerance to reverse ESD voltage can be enhanced, thereby improving reliability of the device.
1. A gallium nitride-based light emitting device comprising an n-type GaN-based clad layer, an active layer, a p-type GaN-based clad layer and a p-side electrode sequentially stacked on a substrate, the light emitting device further comprising:
an n-side electrode formed on one region of the n-type GaN-based clad layer; and
two or more MIM type tunnel junctions formed on the other regions of the n-type GaN-based clad layer, wherein each of MIM type tunnel junctions comprises a lower metal layer formed on the n-type GaN-based clad layer and electrically connected to the n-side electrode while being spaced from the n-side electrode, an insulating film formed on the lower metal layer, and an upper metal layer formed on the insulating film.
2. The light emitting device as set forth in claim 1 , wherein the upper metal layer has a multilayer structure comprising two or more layers.
3. The light emitting device as set forth in claim 1 , wherein the lower metal layer comprises the same material as that of the n-side electrode.
4. The light emitting device as set forth in claim 1 , further comprising:
a transparent electrode layer between the p-type GaN-based clad layer and the p-side electrode.
5. The light emitting device as set forth in claim 4 , wherein the transparent electrode layer extends to an upper surface of the insulating film, and constitutes at least a portion of the upper metal layer.
6. The light emitting device as set forth in claim 5 , wherein the upper metal layer comprises a metal layer formed on the transparent electrode layer and comprising the same material as that of the p-side electrode.
7. The light emitting device as set forth in claim 4 , wherein the upper electrode layer comprises the same material as that of the p-side electrode.
8. The light emitting device as set forth in claim 4 , wherein the transparent electrode layer comprises at least one selected from the group consisting of ITO, SnO 2 , double layers of Ni/Au, an alloy of Ni and Au, ZnO, and MgO.
9. The light emitting device as set forth in claim 1 , wherein the two or more MIM type tunnel junctions are spaced the same distance from the p-side electrode.
10. The light emitting device as set forth in claim 1 , wherein the p-side electrode comprises at least one selected from the group consisting of Ti, Au, Ni, an alloy of Au and Al, an alloy of Au and Ti, an alloy of Au and Cu, a Mn alloy, a La alloy, a Ni alloy, and a Mg alloy.
11. The light emitting device as set forth in claim 1 , wherein the n-side electrode comprises at least one selected from the group consisting of Cr, Ti, Ni, Au, Al, Ta, Hf, AuGe alloy, ZnO, and ITO.
12. The light emitting device as set forth in claim 1 , wherein the insulating film comprises a material selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide, silicon nitride and polyimide.
13. The light emitting device as set forth in claim 1 , wherein the insulating film has a thickness of 10 to 3,000 Å.
14. The light emitting device as set forth in claim 13 , wherein the insulating film has a thickness of 100 to 1,000 Å.