Light emitting devices having a reflective bond pad and methods of fabricating light emitting devices having reflective bond pads
View Patent ↗Light emitting devices include an active region of semiconductor material and a first contact on the active region. The first contact is configured such that photons emitted by the active region pass through the first contact. A photon absorbing wire bond pad is provided on the first contact. The wire bond pad has an area less than the area of the first contact. A reflective structure is disposed between the first contact and the wire bond pad such that the reflective structure has substantially the same area as the wire bond pad. A second contact is provided opposite the active region from the first contact. The reflective structure may be disposed only between the first contact and the wire bond pad. Methods of fabricating such devices are also provided.
1. A light emitting device, comprising:
an active region comprising semiconductor material;
a first contact metal on the active region, the first contact metal having a first face adjacent the active region and a second face remote from the active region, and being sufficiently thin such that photons emitted by the active region pass through the first contact metal from the first face to the second face;
a photon absorbing wire bond pad on the second face of the first contact metal, the wire bond pad having an area less than the area of the first contact metal;
a reflective structure disposed entirely between the second face of the first contact metal and the wire bond pad and extending on the second face of the first contact metal to be substantially congruent with the wire bond pad; and
a second contact metal opposite the active region from the first contact metal,
wherein the reflective structure comprises a layer of silver or aluminum directly on the second face of the first contact metal.
2. The light emitting device of claim 1 , further comprising a p-type semiconductor material disposed between the first contact metal and the active region.
3. The light emitting device of claim 1 , further comprising an n-type semiconductor material between the first contact and the active region.
4. The light emitting device of claim 1 , wherein the active region comprises a Group III-nitride based active region.
5. The light emitting device of claim 1 , wherein the layer of reflective metal is self-aligned with the wire bond pad.
6. A method of fabricating a light emitting device, comprising:
forming an active region of semiconductor material;
forming a first contact metal on the active region, the first contact metal having a first face adjacent the active region and a second face remote from the active region, and being sufficiently thin such that photons emitted by the active region pass through the first contact metal from the first face to the second face;
forming a reflective structure entirely on the second face of the first contact metal and having an area less than an area of the first contact metal;
forming a photon absorbing wire bond pad on reflective structure, the wire bond pad being substantially congruent to the reflective structure; and
forming a second contact metal opposite the active region from the first contact metal,
wherein forming a reflective structure comprises forming a reflective structure that comprises a layer of silver or aluminum directly on the second face of the first contact metal.
7. The method of claim 6 , further comprising forming a p-type semiconductor material disposed between the first contact metal and the active region.
8. The method of claim 6 , further comprising forming an n-type semiconductor material between the first contact and the active region.
9. The method of claim 6 , wherein forming an active region comprises forming a Group III-nitride based active region.
10. The method of claim 6 , wherein forming a reflective structure comprises forming a layer of reflective metal entirely on the second face of the first contact metal.
11. The method of claim 6 , wherein forming a reflective structure and forming a wire bond pad comprises:
forming a mask layer on the first contact, the mask layer having an opening that exposes a portion of the first contact corresponding to the location of the wire bond pad on the first contact;
depositing a reflective metal layer in the opening of the mask layer; and
forming the wire bond pad on the reflective metal layer in the opening of the mask layer.