Series connected segmented LED
View Patent ↗A light source and method for making the same are disclosed. The light source includes a substrate, and a light emitting structure that is divided into segments. The light emitting structure includes a first layer of semiconductor material of a first conductivity type deposited on the substrate, an active layer overlying the first layer, and a second layer of semiconductor material of an opposite conductivity type from the first conductivity type overlying the active layer. A barrier divides the light emitting structure into first and second segments that are electrically isolated from one another. A serial connection electrode connects the first layer in the first segment to the second layer in the second segment. A power contact is electrically connected to the second layer in the first segment, and a second power contact is electrically connected to the first layer in the second segment.
1. A light source comprising
a substrate;
a light emitting structure comprising:
a first layer of semiconductor material of a first conductivity type deposited on said substrate;
an active layer overlying said first layer; and
a second layer of semiconductor material of an opposite conductivity type from said first conductivity type overlying said active layer;
a transparent conducting layer overlying said second layer of semiconductor material;
a barrier that divides said light emitting structure into first and second segments that are electrically isolated from one another;
a serial connection electrode that connects said first layer in said first segment to said transparent conducting layer in said second segment;
an insulating layer between said second layer and said transparent conducting layer in said second segment, said insulating layer underlying said serial connection electrode such that current flowing from said serial connection electrode is blocked by said insulating layer in a region underlying said serial connection electrode;
a first power contact electrically connected to said second layer in said first segment; and
a second power contact electrically connected to said first layer in said second segment, wherein said first and second segments generate light when a potential difference is created between said first and second power contacts.
2. The light source of claim 1 wherein said barrier comprises a trench extending through said light emitting structure.
3. The light source of claim 2 wherein said serial connection electrode comprises a layer of electrically conducting material deposited in said trench, said trench having an insulating layer that prevents said layer of electrically conducting material from making direct contact with said first layer or said active layer in said second segment.
4. The light source of claim 2 comprising an insulating layer underlying a portion of said serial connection electrode that overlies said active layer in said second segment.
5. The light source of claim 3 wherein said electrically conducting material comprises a metal.
6. The light source of claim 3 wherein said electrically conducting material comprises ITO.
7. The light source of claim 2 wherein said harrier is transparent to light traveling in said first layer.
8. A method for fabricating a light source, said method comprising
depositing a light emitting structure on a substrate, said light emitting structure comprising:
a first layer of semiconductor material of a first conductivity type deposited on said substrate;
an active layer overlying said first layer;
a second layer of semiconductor material of an opposite conductivity type from said first conductivity type overlying said active layer;
an insulting pad on said second layer of semiconductor material; and
a transparent conducting layer overlying said second layer of semiconductor material and said insulating pad;
generating a barrier that divides said light emitting structure into first and second segments that are electrically isolated from one another;
depositing a serial connection electrode that connects said first layer in said first segment to said transparent conducting layer in said second segment, said serial connection electrode overlying said insulating pad such that current flowing from said serial connection electrode is blocked by said insulating pad in a region underlying said serial connection electrode;
providing a first power contact electrically connected to said second layer in said first segment; and
providing a second power contact electrically connected to said first layer in said second segment, wherein said first and second segments generate light when a potential difference is created between said first and second power contacts.
9. The method of claim 8 wherein said barrier is generated by etching a trench extending through said light emitting structure to said substrate.
10. The method of claim 9 wherein depositing said serial connection electrode comprises depositing an insulating layer in said trench, and depositing a layer of electrically conducting material in said trench over said insulating layer, said insulating layer preventing said layer of electrically conducting material from making direct contact with said first layer or said active layer in said second segment.
11. The method of claim 9 wherein said insulating layer underlies a portion of said serial connection electrode that overlies said active layer in said second segment.
12. The method of claim 10 wherein said electrically conducting material comprises a metal.
13. The method of claim 10 wherein said electrically conducting material comprises ITO.
14. The method of claim 9 wherein said barrier is transparent to light traveling in said first layer.