Optoelectronic substrate and methods of making same

Abstract

A method of producing an optoelectronic substrate by detaching a thin layer from a semi-conducting nitride substrate and transferring it to an auxiliary substrate to provide at least one semi-conducting nitride layer thereon, metallizing at least a portion of the surface of the auxiliary substrate that includes the transferred nitride layer, bonding to a final substrate the metallized surface portion of the transferred nitrate layer of the auxiliary substrate, and removing the auxiliary substrate to provide an optoelectronic substrate comprising a semi-conducting nitride surface layer over a subjacent metallized portion and a supporting final substrate. Resultant optoelectronic substrates having low dislocation densities are also included.

1  An optoelectronic substrate comprising:
 a substrate;   a metallized layer disposed over at least a portion of the substrate; and   at least one nitride layer disposed over the metallized layer, wherein the dislocation density of the nitride layer(s) is less than about 10 8 /cm 2 .   
     
     
         2 . The optoelectronic substrate of  claim 1 , wherein the dislocation density of the nitride layer(s) is less than about 10 7 /cm 2 . 
     
     
         3 . The optoelectronic substrate of  claim 1 , wherein the substrate comprises at least one of silicon, silicon carbide or copper. 
     
     
         4 . The optoelectronic substrate of  claim 1 , wherein the metallized layer is disposed over a sufficient portion of the final substrate to increase electrical contact between the final substrate and the at least one nitride layer. 
     
     
         5 . The optoelectronic substrate of  claim 1 , wherein the metallized layer comprises an alloy. 
     
     
         6 . The optoelectronic substrate of  claim 1 , wherein the metallized layer comprises Ni/Au, Pt, rhodium or combinations thereof. 
     
     
         7 . The optoelectronic substrate of  claim 1 , wherein the nitride layer is a semi-conducting Group III metal nitride layer having a Group III metal face and a prepared nitrogen face with the prepared nitrogen face of the nitride substrate exposed and the Group III metal face positioned facing the metallized layer. 
     
     
         8 . The optoelectronic substrate of  claim 7 , wherein the prepared nitrogen face has a dislocation density of less than about 10 6 /cm 2 , a substrate planarity in the range of 20 micrometers and a surface roughness of less than 0.3 nm RMS measured with an atomic force microscope over a field of 1×1 μm 2 . 
     
     
         9 . The optoelectronic substrate of  claim 7 , which further comprises a dielectric layer on the prepared nitrogen face. 
     
     
         10 . The optoelectronic substrate of  claim 7 , which further comprises at least one reflection layer between the Group III metal face of the nitride layer and the metallized layer which serves as a mirror so light emitted from nitride layer is not absorbed by the substrate. 
     
     
         11 . The optoelectronic substrate of  claim 1 , wherein the reflection layer is gold, aluminium, or silver. 
     
     
         12 . The optoelectronic substrate of  claim 1 , wherein the nitride layer comprises GaN or AlN. 
     
     
         13 . The optoelectronic substrate of  claim 1 , wherein the nitride layer includes at least one epitaxial nitride layer comprising at least one of n-type GaN, InGaN, AlGaN, undoped GaN, or p-type GaN. 
     
     
         14 . An optoelectronic intermediate assembly comprising:
 an auxiliary substrate; and   a thin layer of group III metal nitride having a group III metal face and a prepared nitrogen face, the prepared nitrogen face having a dislocation density of less than about 10 8 /cm 2 , a surface planarity in the range of 20 micrometers and a surface roughness of less than 0.3 nm RMS measured with an atomic force microscope over a field of 1×1 μm 2  with the prepared nitrogen face bonded to the auxiliary substrate.   
     
     
         15 . The optoelectronic substrate of  claim 14 , wherein the thin layer of group III metal nitride includes at least one epitaxial nitride layer comprising at least one of n-type GaN, InGaN, AlGaN, undoped GaN, or p-type GaN. 
     
     
         16 . The optoelectronic substrate of  claim 14 , wherein the auxiliary substrate includes silicon, GaAs or ZnO. 
     
     
         17 . The optoelectronic substrate of  claim 14 , wherein the nitride layer comprises GaN or AlN.