Passivation for a semiconductor light emitting device
View Patent ↗In embodiments of the invention, a passivation layer is disposed over a side of a semiconductor structure including a light emitting layer disposed between an n-type region and a p-type region. A material configured to adhere to an underfill is disposed over an etched surface of the semiconductor structure.
1. A method, comprising:
providing a wafer comprising a plurality of semiconductor light emitting devices, each light emitting device comprising an active region disposed between an n-type region and a p-type region, and a metal bonding layer coupled to an exposed portion of the n-type region;
disposing a first material comprising a dielectric layer on the wafer, including disposing a portion of the dielectric layer directly on a first area of the exposed portion of the n-type region that is located between two semiconductor light emitting devices;
disposing a second material comprising an underfill in areas between the wafer and a mount, including disposing the underfill directly on (1) the portion of the dielectric layer and (2) a second area of the exposed portion of the n-type layer, the portion of the dielectric layer improving adhesion of the underfill to the exposed portion of the n-type layer; and
attaching the wafer to the mount.
2. The method of claim 1 , further comprising separating the plurality of semiconductor light emitting devices by singulating the wafer in the first area where the portion of the dielectric layer is disposed.
3. The method of claim 1 , wherein the dielectric layer comprises Si 3 N 4 .
4. The method of claim 1 , further comprising a passivation layer configured to prevent contaminants from contacting the semiconductor light emitting device.
5. The method of claim 2 , wherein the separating the plurality of semiconductor light emitting devices by singulating the wafer further comprises one of sawing, laser scribing, and breaking.
6. The method of claim 2 , wherein the separating the plurality of semiconductor light emitting devices by singulating the wafer further comprises singulating after the attaching the structure to a mount.
7. The method of claim 1 , wherein the attaching the structure to the mount comprises attaching the wafer by the metal bonding layer to the mount.
8. The method of claim 1 , further comprising forming an n-contact in a third area of the exposed portion of the n-type region the second area being between the first area and the third area.
9. The method of claim 8 , further comprising forming a p-contact on the p-type region and forming a guard layer on the p-contact.
10. The method of claim 9 , wherein:
the disposing the dielectric layer on the wafer includes disposing the dielectric layer over the guard layer and the exposed portion of the n-type region; and
the disposing the portion of the dielectric layer directly on the first area of the exposed portion of the n-type region comprises partially removing the dielectric layer on the exposed portion of the n-type region to leave behind the portion of the dielectric layer on the first area of the exposed portion of the n-type region.
11. The method of claim 10 , wherein the metal bonding layer is formed over the n-contact.
12. A method of making a light emitting device, comprising:
providing a wafer comprising a plurality of semiconductor light emitting devices on a growth substrate, each light emitting device comprising: a light emitting layer disposed between an n-type region and a p-type region, an n-contact on an exposed portion of the n-type region, and a metal bonding layer over the n-contact;
disposing a passivation layer on the wafer, including over an outer side of the metal bonding layer, over an outer side of the n-contact, and on top of the exposed portion of the n-type region in a street between two semiconductor light emitting devices;
disposing an underfill in areas between the wafer and a mount, including over an outer side of the passivation layer, the passivation layer improving adhesion of the underfill to the wafer;
attaching the wafer to the mount; and
separating the two semiconductor light emitting devices by singulating the wafer in the street.
13. The method of claim 12 , wherein the passivation layer is at least one of an insulating layer, a dielectric layer, AlN, TiN, SiO 2 , SiN x O y , SiN x , and Si 3 N 4 .
14. The method of claim 12 , wherein the passivation layer is configured to reflect light emitted by the light emitting layer.
15. The method of claim 12 , wherein the passivation layer is a multilayer dielectric stack.
16. The method of claim 12 , further comprising removing a part of the exposed portion of the n-type region to expose a portion of the growth substrate in or adjacent to the street, wherein the disposing the passivation layer on the wafer further comprises disposing the passivation layer over an outer side of the exposed portion of the n-type region and on top of the exposed portion of the growth substrate.