Techniques for forming optoelectronic devices

Abstract

Embodiments relate to use of a particle accelerator beam to form thin films of material from a bulk substrate are described. In particular embodiments, a bulk substrate having a top surface is exposed to a beam of accelerated particles. In certain embodiments, this bulk substrate may comprise GaN; in other embodiments this bulk substrate may comprise (111) single crystal silicon. Then, a thin film or wafer of material is separated from the bulk substrate by performing a controlled cleaving process along a cleave region formed by particles implanted from the beam. In certain embodiments this separated material is incorporated directly into an optoelectronic device, for example a GaN film cleaved from GaN bulk material. In some embodiments, this separated material may be employed as a template for further growth of semiconductor materials (e.g. GaN) that are useful for optoelectronic devices.

1 .- 17 . (canceled) 
     
     
         18 . A workpiece for formation of an optoelectronic device, the workpiece comprising:
 a layer of crystalline material having a lattice constant compatible with formation of an overlying film of semiconductor material; and   a substrate bonded to a first surface of the layer of crystalline material opposite to a second surface of the layer of material upon which the overlying film of semiconductor material is to be formed, the substrate having a coefficient of thermal expansion approximately equal to a coefficient of thermal expansion of the layer of crystalline material.   
     
     
         19 . The workpiece as in  claim 18  wherein the layer of crystalline material exhibits a level of stress lower than a threshold value sufficient to nucleate and propagate defects within the crystalline material. 
     
     
         20 . The workpiece as in  claim 18  wherein mismatch between the substrate and the layer of crystalline material develops the level of stress insufficient to generate more than about 1×10 4  defects/cm 2 . 
     
     
         21 . The workpiece as in  claim 18  wherein mismatch between the substrate and the layer of crystalline material develops the level of stress insufficient to generate more than 1×10 6  defects/cm 2 . 
     
     
         22 . The workpiece as in  claim 18  wherein the layer of crystalline material comprises a non-thermal stress relaxed material. 
     
     
         23 . The workpiece as in  claim 18  wherein the layer of crystalline material comprises GaN and the substrate comprises metal. 
     
     
         24 . The workpiece as in  claim 23  wherein a coefficient of thermal expansion of the metal substrate is approximately equal to a coefficient of thermal expansion of the GaN at a temperature range of between about 900-1200° C. 
     
     
         25 . The workpiece as in  claim 18  wherein the substrate is releasably bonded to the layer of crystalline material based upon a roughness of the substrate and/or a roughness of the layer of material. 
     
     
         26 . The workpiece as in  claim 18  wherein the substrate is releasably bonded to the layer of crystalline material based upon an intervening sacrificial layer. 
     
     
         27 . The workpiece as in  claim 26  wherein the intervening sacrificial layer comprises an oxide. 
     
     
         28 .- 44 . (canceled)