P-contact with more uniform injection and lower optical loss
View Patent ↗The current distribution across the p-layer ( 130 ) of a semiconductor device is modified by purposely inhibiting current flow through the p-layer ( 130 ) in regions ( 310 ) adjacent to the guardsheet ( 150 ), without reducing the optical reflectivity of any part of the device. This current flow may be inhibited by increasing the resistance of the p-layer that is coupled to the p-contact ( 140 ) along the edges and in the corners of contact area. In an example embodiment, the high-resistance region ( 130 ) is produced by a shallow dose of hydrogen-ion (H+) implant after the p-contact ( 140 ) is created. Similarly, a resistive coating may be applied in select regions between the p-contact and the p-layer.
1. A method comprising:
creating a light emitting element comprising an active region between an n-layer and a p-layer,
providing a p-contact to the p-layer, the p-contact being coupled to the p-layer,
creating a current-inhibiting region by using a shallow low dose ion implantation in a periphery of the p-contact, wherein the current-inhibiting region provides a non-uniform current flow from the p-contact to the p-layer,
providing a p-pad coupled to the p-contact to facilitate coupling to an external source of power, and
providing an n-pad coupled to the n-layer to facilitate coupling to the external source of power.
2. The method of claim 1 , wherein the p-contact includes silver.
3. The method of claim 1 , wherein the current-inhibiting region corresponds to a periphery of the p-contact.
4. The method of claim 1 , wherein the current-inhibiting region includes curved corners with a radius of curvature greater than a radius of curvature of the p-contact.
5. The method of claim 1 , wherein the current-inhibiting region corresponds to a region of the p-contact closest to a contact region between the n-pad and the n-layer.
6. A method comprising:
creating a light emitting element comprising an active region between an n-layer and a p-layer,
providing a p-contact to the p-layer, the p-contact being coupled to the p-layer,
creating a current-inhibiting region by providing a material that improves ohmic contact about a center of the p-contact, omitting the material from the periphery of the p-contact, and reducing a doping of the periphery the p-contact, wherein the current-inhibiting region provides a non-uniform current flow from the p-contact to the p-layer,
providing a p-pad coupled to the p-contact to facilitate coupling to an external source of power, and
providing an n-pad coupled to the n-layer to facilitate coupling to the external source of power.
7. The method of claim 6 , wherein the material that improves ohmic contact includes NiO.
8. A light emitting device comprising:
an n-layer,
a p-layer,
a light emitting layer between the n-layer and the p-layer,
an n-pad for coupling to the n-layer,
a p-pad for coupling to the p-layer, and
a p-contact that couples the p-pad to the p-layer to facilitate a current injection through the p-layer,
wherein the p-contact is configured to inhibit the current injection through the p-layer in a current-inhibiting region of the p-contact, and the current-inhibiting region includes a shallow low dose ion-injected region in the p-contact.
9. The light emitting device of claim 8 , wherein the current-inhibiting region corresponds to a region of the p-contact that provides a maximum current injection in the absence of the current-inhibiting region.
10. The light emitting device of claim 8 , wherein the current-inhibiting region corresponds to a periphery of the p-contact.
11. The light emitting device of claim 8 , wherein the p-contact includes silver.
12. The light emitting device of claim 8 , wherein the current-inhibiting region includes curved corners with a radius of curvature greater than a radius of curvature of the p-contact.
13. The light emitting device of claim 8 , wherein the current-inhibiting region corresponds to a region of the p-contact closest to a contact region between the n-pad and the n-layer.
14. The light emitting device of claim 8 , wherein the current-inhibiting region of the p-contact serves to improve uniformity of the current injection through the light emitting layer.
15. A light emitting device comprising:
an n-layer,
a p-layer,
a light emitting layer between the n-layer and the p-layer,
an n-pad for coupling to the n-layer,
a p-pad for coupling to the p-layer, and
a p-contact that couples the p-pad to the p-layer to facilitate a current injection through the p-layer,
wherein the p-contact is configured to inhibit the current injection through the p-layer in a current-inhibiting region at a periphery of the p-contact, the p-contact is reflective of light emitted by the light emitting layer and the current-inhibiting region includes a substantially transparent resistive coating between the p-contact and the p-layer.
16. The light emitting device of claim 15 , wherein the current-inhibiting region of the p-contact serves to improve uniformity of the current injection through the light emitting layer.
17. A light emitting device comprising:
an n-layer,
a p-layer,
a light emitting layer between the n-layer and the p-layer,
an n-pad for coupling to the n-layer,
a p-pad for coupling to the p-layer, and
a p-contact that couples the p-pad to the p-layer to facilitate a current injection through the p-layer,
wherein the p-contact is configured to inhibit the current injection through the p-layer in a current-inhibiting region at a periphery of the p-contact, the p-contact includes a material that improves an ohmic contact about a center of the p-contact, and the current-inhibiting region corresponds to an absence of this material and a reduced doping at the periphery of the p-contact.
18. The light emitting device of claim 17 , wherein the material that improves the ohmic contact includes NiO.
19. The light emitting device of claim 17 , wherein the current-inhibiting region of the p-contact serves to improve uniformity of the current injection through the light emitting layer.