Solid state lighting devices with improved current spreading and light extraction and associated methods
View Patent ↗Solid state lighting (“SSL”) devices with improved current spreading and light extraction and associated methods are disclosed herein. In one embodiment, an SSL device includes a solid state emitter (“SSE”) that has a first semiconductor material, a second semiconductor material spaced apart from the first semiconductor material, and an active region between the first and second semiconductor materials. The SSL device can further include a first contact on the first semiconductor material and a second contact on the second semiconductor material and opposite the first contact. The second contact can include one ore more interconnected fingers. Additionally, the SSL device can include an insulative feature extending from the first contact at least partially into the first semiconductor material. The insulative feature can be substantially aligned with the second contact.
1. A solid state lighting (SSL) device, comprising:
a solid state emitter (SSE) having a first semiconductor material, a second semiconductor material spaced apart from the first semiconductor material, and an active region between the first and second semiconductor materials, wherein the second semiconductor material has an emission surface;
a first contact on the first semiconductor material;
a second contact on the second semiconductor material and opposite to the first contact, the second contact having a plurality of interconnected conductive fingers; and
an insulative feature extending from the first contact at least partially into the first semiconductor material, the insulative feature having a plurality of interconnected insulative fingers, wherein the insulative feature comprises a transparent dielectric material having a backside;
the SSL device further comprises a reflective material at the backside of the transparent dielectric material;
each conductive finger is superimposed over a corresponding insulative fingers;
the SSE comprises non-contact areas outboard the area beneath the second contact; and
the insulative feature is configured to: (a) eliminate a direct current path orthogonal to the emission surface between the first and second contacts and (b) increase current spreading in the non-contact areas.
2. The SSL device of claim 1 wherein:
the second contact comprises a conductive cross member connecting the plurality of conductive fingers; and
the insulative feature comprises an insulative cross member connecting the plurality of insulative fingers, wherein the conductive cross member is superimposed over the insulative cross member.
3. The SSL device of claim 1 wherein the reflective material covers a backside of the dielectric material and the first contact.
4. The SSL device of claim 1 wherein the insulative feature extends at least to the second semiconductor material.
5. The SSL device of claim 1 wherein the insulative feature extends through the first semiconductor material and at least a portion of the active region.
6. The SSL device of claim 1 wherein a reflective material defines the first contact.
7. The SSL device of claim 1 wherein the insulative feature comprises a gas-filled gap.
8. The SSL device of claim 1 wherein:
the individual conductive fingers have a first width;
the individual insulative fingers have a second width; and
the second width is at least equal to the first width.
9. The SSL device of claim 1 wherein:
the second contact comprises a conductive cross member connecting the plurality of conductive fingers; and
the insulative feature comprises an insulative cross member connecting the plurality of insulative fingers, wherein the insulative cross member is aligned with the conductive cross member.
10. A solid state lighting (SSL) device, comprising:
a solid state emitter (SSE) having a first side and a second side opposite the first side;
a first contact at the first side;
a second contact at the second side, the second contact having a plurality of interconnected conductive fingers; and
an insulative feature at the first side of the SSE, the insulative feature having a plurality of interconnected insulative fingers, wherein the insulative feature is configured to increase current spreading in non-contact areas outboard of the second contact of the SSE, wherein the insulative feature comprises a transparent dielectric material having a backside;
the SSL comprises a reflective material at the backside of the transparent dielectric material;
the SSE comprises a first semiconductor material at the first side of the SSE, a second semiconductor material at the second side of the SSE, and an active region between the first and second semiconductor materials;
each conductive finger is superimposed over a corresponding insulative finger; and
the insulative feature extends at least to the second semiconductor material and is positioned to block a direct current path orthogonal to the second side between the first and second contacts and thereby reduce the current density under the plurality of interconnected conductive fingers.
11. The SSL device of claim 10 wherein the insulative feature comprises a gas-filled gap.