Series connected segmented LED
View Patent ↗A light source and method for making the same are disclosed. The light source includes a conducting 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 electrically connected to the first layer in the second segment.
1. A light emitting device comprising:
a substrate;
a light emitting structure bonded to the substrate and comprising:
a first semiconductor layer of a first conductivity type,
an active layer on the first semiconductor layer, and
a second semiconductor layer of an opposite conductivity type from the first conductivity type formed on the active layer;
a trench that divides the light emitting structure into first and second segments that are electrically isolated from one another;
a mirror in electrical contact with the first semiconductor layer in each of the first and second segments;
a barrier layer formed adjacent to the mirror and between the mirror and the substrate in each of the first and second segment, an upper surface of the barrier layer and a lower surface of the first semiconductor layer being positioned in a substantially same plane, the upper surface of the barrier layer partially exposed by the trench; and
a connection electrode contacting the upper surface of the barrier layer in the first segment exposed by the trench and connecting the barrier layer in the first segment to the second semiconductor layer in the second segment so as to electrically connect the first semiconductor layer in the first segment to the second semiconductor layer in the second segment,
wherein the substrate comprises:
a semiconductor material of a first conductivity type; and
first and second isolation regions that electrically isolate the mirror in the first and second segments from each other, the isolation regions comprising a region of a second conductivity type in the semiconductor material.
2. The light emitting device of claim 1 , further comprising:
a first power contact electrically connected to the second semiconductor layer in the first segment; and
a second power contact electrically connected to the first semiconductor layer in the second segment,
wherein the first and second segments generate light when a potential difference is created between the first and second power contacts.
3. The light emitting device of claim 1 , wherein the isolation regions comprise an insulating layer between the mirror and the substrate.
4. The light emitting device of claim 1 , wherein the substrate is bonded to the light emitting structure by a layer of metal.
5. The light emitting device of claim 1 , wherein the first semiconductor layer comprises a p-type GaN family member.
6. The light emitting device of claim 1 , wherein the substrate comprises silicon.
7. The light emitting device of claim 1 , wherein the first semiconductor layer comprises n-type GaN family member.