Optoelectronic device with transparent insulated current blocking region and uniform current spreading
An optoelectronic device includes a semiconductor stack including a top surface; a current blocking region, including a first pad portion formed on the semiconductor stack and wherein the current blocking region includes transparent insulated material; a first opening, formed in the first pad portion, exposing the top surface of the semiconductor stack; a transparent conductive layer, covering the top surface of the semiconductor stack, including a second opening overlapping the first opening; and a first electrode, formed on the semiconductor stack, including a first pad electrode formed on the first pad portion of the current blocking region; wherein the first pad electrode contacts the semiconductor stack through the first opening and the second opening; wherein the first opening includes a first area, the first pad portion and the first opening compose a total area, and a ratio of the first area to the total area is between 10% and 40%.
1. An optoelectronic device, comprising:
a semiconductor stack, comprising a top surface;
a current blocking region, comprising a first pad portion formed on the semiconductor stack and wherein the current blocking region comprises transparent insulated material;
a first opening, formed in the first pad portion, exposing the top surface of the semiconductor stack;
a transparent conductive layer, covering the top surface of the semiconductor stack, comprising a second opening overlapping the first opening; and
a first electrode, formed on the semiconductor stack, comprising a first pad electrode formed above the first pad portion of the current blocking region;
wherein the first pad electrode contacts the semiconductor stack through the first opening and the second opening; and
wherein the first opening comprises a first area, the first pad portion and the first opening compose a total area, and a ratio of the first area to the total area is between 10% and 40%.
2. The optoelectronic device according to claim 1 , wherein the current blocking region comprises distributed Bragg reflector.
3. The optoelectronic device according to claim 1 , wherein a width of the first opening is smaller than or equal to 10 μm.
4. The optoelectronic device according to claim 1 , wherein the first pad portion is separated into a plurality of portions by the first opening.
5. The optoelectronic device according to claim 1 , wherein in a top view, the first opening and the second opening have different shapes.
6. The optoelectronic device according to claim 5 , wherein the first opening comprises elongated shape.
7. The optoelectronic device according to claim 5 , wherein the first opening comprises a plurality of opening branches.
8. The optoelectronic device according to claim 7 , wherein one of the plurality of opening branches comprises elongated shape.
9. The optoelectronic device according to claim 7 , wherein the plurality of opening branches is symmetrically arranged in the first pad portion.
10. The optoelectronic device according to claim 7 , wherein one of the plurality of opening branches comprises a plurality of sections separated from each other.
11. The optoelectronic device according to claim 7 , wherein a contour which is composed by an outmost edge of the first pad portion and a pseudo edge of the first opening includes a composed shape and wherein one of the plurality of opening branches comprises an end pointing to a center of the composed shape.
12. The optoelectronic device according to claim 1 , wherein a contour which is composed by an outmost edge of the first pad portion and a pseudo edge of the first opening includes a composed shape, and the composed shape and a shape of the first pad electrode are different.
13. The optoelectronic device according to claim 12 , wherein the composed shape is a rectangular shape or a rectangle with curve corners.
14. The optoelectronic device according to claim 1 , wherein a width of the first pad electrode is smaller than a width of the second opening.
15. The optoelectronic device according to claim 1 , wherein the transparent conductive layer does not contact the first pad portion.
16. The optoelectronic device according to claim 1 , wherein the transparent conductive layer covers a part of the first pad portion and a part of the first opening.
17. The optoelectronic device according to claim 1 , wherein:
the semiconductor stack comprises a first semiconductor layer, a second semiconductor layer on the first semiconductor layer and an active layer therebetween;
the current blocking region is formed on the second semiconductor layer; and
the first pad electrode contacts the second semiconductor layer.
18. The optoelectronic device according to claim 17 , further comprising a second electrode on the first semiconductor layer, and wherein the second electrode comprises a second pad electrode and a second finger electrode extending along an edge of the optoelectronic device.
19. The optoelectronic device according to claim 1 , wherein the current blocking region further comprises a first finger portion; and wherein the first electrode further comprises a first finger electrode extending from the first pad electrode and formed on the first finger portion.
20. The optoelectronic device according to claim 19 , wherein the first finger portion is separated from the first pad portion.