Light emitting diode having undoped and unintentionally doped nitride transition layer
View Patent ↗A method of forming electronic device precursors and devices with reduced cracking in relevant layers is disclosed along with resulting structures. The method includes the steps of growing a transition layer of undoped Group III nitride on a substrate that is other than a Group III nitride, growing an active structure of Group III nitride on the undoped layer, and removing the substrate from the undoped layer.
1. A light emitting diode comprising:
a Group III nitride transition layer having a thickness of between about 0.3 and 1.0 microns and a dopant concentration less than 1E17 cm −3 ;
an n-type Group III nitride doped layer directly on said Group III nitride transition layer;
a first ohmic contact that extends from the n-type Group III nitride doped layer through an opening in the Group III nitride transition layer;
at least one active layer on said Group III nitride doped layer opposite to the Group III nitride transition layer;
a p-type Group III nitride layer on said at least one active layer opposite to the Group III nitride doped layer configured to generate light emission when current is applied across said p-type Group III nitride and said n-type Group III nitride doped layer; and
a second ohmic contact that extends from the p-type Group III nitride layer, wherein the first and second ohmic contacts are used to apply the current across said p-type Group III nitride layer and said n-type Group III nitride doped layer.
2. A light emitting diode according to claim 1 wherein said Group III nitride transition layer comprises aluminum gallium nitride.
3. A light emitting diode according to claim 2 wherein the atomic percentage of aluminum is about 20 percent.
4. A light emitting diode according to claim 1 wherein the at least one active layer comprises an active layer between said p-type layer and said n-type layer.
5. A light emitting diode according to claim 4 comprising ohmic contacts for said p-type layer and said n-type layer for applying a current across said active layer to generate an emission.
6. A display that incorporates the light emitting diode of claim 1 .
7. A light emitting diode according to claim 1 comprising respective ohmic contacts for applying a voltage across and generating a current through said p-type and n-type layers.
8. A light emitting diode according to claim 1 wherein the Group III nitride transition layer has a resistivity of at least about 0.1 ohm centimeters.
9. A light emitting diode according to claim 1 wherein the Group III nitride transition layer has a dopant concentration less than 1E17 cm −3 .
10. A light emitting diode according to claim 9 wherein the dopant concentration of the undoped Group III nitride transition layer is greater than about 1E15 cm −3 .
11. A light emitting diode according to claim 1 wherein said the undoped Group III nitride transition layer has a lenticular emitting surface.
12. A light emitting diode according to claim 1 , wherein said Group III nitride transition layer has a thickness of about 0.3 micron.
13. A light emitting diode according to claim 1 , further comprising a discontinuous Group III nitride layer positioned between said Group III nitride transition layer and a substrate selected from the group consisting of silicon carbide and sapphire.
14. A light emitting diode according to claim 1 , wherein the header provides electrical connection to the p-type Group III nitride layer and the n-type Group III nitride doped layer.