Vertical geometry InGaN LED

Abstract

A vertical geometry light emitting diode is disclosed that is capable of emitting light in the red, green, blue, violet and ultraviolet portions of the electromagnetic spectrum. The light emitting diode includes a conductive silicon carbide substrate, an InGaN quantum well, a conductive buffer layer between the substrate and the quantum well, a respective undoped gallium nitride layer on each surface of the quantum well, and ohmic contacts in a vertical geometry orientation.

1. A vertical geometry  light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
 a conductive silicon carbide substrate; 
 an InGaN quantum well;  
 a conductive buffer layer between said substrate and said quantum well; 
 a respective  first undoped gallium nitride layer on each  a first surface of said quantum well;  
 a second layer consisting of undoped gallium nitride on a second surface of said quantum well opposite said first surface; and  
 ohmic contacts in a vertical geometry orientation; 
 a doped layer of gallium nitride between said buffer and said undoped gallium nitride layer; 
 an undoped layer of aluminum gallium nitride on the surface of said second undoped gallium nitride layer on said quantum well that is opposite from said substrate and buffer ; and  
 a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.  
 
     
     
       2. A vertical geometry  light emitting diode according to  claim 1  and further comprising a doped gallium nitride layer on said doped aluminum gallium nitride layer. 
     
     
       3. A vertical geometry  light emitting diode according to  claim 2  wherein:
 said substrate, said buffer layer and said  first undoped gallium nitride layer adjacent said buffer are all  is n-type; and  
 said doped layer of aluminum gallium nitride and doped layer of gallium nitride thereon are  is p-type.  
 
     
     
       4. A vertical geometry  light emitting diode according to  claim 1  wherein said quantum well comprises a multiple quantum well. 
     
     
       5. A pixel that includes a light emitting diode according to  claim 1 .  A light emitting diode according to  claim 1  further comprising:
   a conductive silicon carbide substrate; and    
   a conductive buffer layer between said substrate and said quantum well.   
 
     
     
       6. A display that includes a plurality of pixels according to  claim 5 .  A light emitting diode according to  claim 1  further comprising:
   an ohmic contact on one surface of said light emitting diode; and    
   another ohmic contact on the opposite surface of said light emitting diode and with said ohmic contacts in a vertical geometry orientation.   
 
     
     
       7. A vertical geometry light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
   an InGaN quantum well;        a respective layer consisting of undoped gallium nitride on each surface of said quantum well;        ohmic contacts in a vertical geometry orientation; a doped layer of gallium nitride below one of said undoped gallium nitride layers;        an undoped layer of aluminum gallium nitride on the surface of the opposite undoped gallium nitride layer; and        a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.     
     
     
       8. A light emitting diode according to  claim 7  and further comprising:
   a conductive silicon carbide substrate; and    
   a conductive buffer layer between said substrate and said quantum well, with said doped gallium nitride layer on said buffer layer.   
 
     
     
       9. A light emitting diode according to  claim 7  comprising a doped gallium nitride layer on said doped aluminum gallium nitride layer. 
     
     
       10. A light emitting diode according to  claim 7  wherein:
   said opposite undoped gallium nitride layer is n - type; and    
   said doped layer of aluminum gallium nitride is p - type.   
 
     
     
       11. A light emitting diode according to  claim 7  wherein said quantum well comprises multiple quantum wells. 
     
     
       12. A light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
   a substrate;        an InGaN quantum well;        a buffer layer between said substrate and said quantum well;        a first undoped gallium nitride layer on a first surface of said quantum well;        a second layer consisting of undoped gallium nitride on a second surface of said quantum well opposite said first surface; and        a doped layer of gallium nitride between said buffer and said first undoped gallium nitride layer;        an undoped layer of aluminum gallium nitride on the surface of said second undoped gallium nitride layer on said quantum well that is opposite from said substrate and buffer; and        a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.     
     
     
       13. A light emitting diode according to  claim 12  further comprising:
   an ohmic contact on one surface of said light emitting diode; and    
   another ohmic contact on the opposite surface of said light emitting diode and with said ohmic contacts in a vertical geometry orientation.   
 
     
     
       14. A light emitting diode according to  claim 13  and further comprising:
   a conductive silicon carbide substrate; and    
   a conductive buffer layer between said substrate and said quantum well, with said doped gallium nitride layer on said buffer layer.   
 
     
     
       15. A light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
   a substrate;        an InGaN quantum well;        a buffer layer between said substrate and said quantum well;        a first undoped gallium nitride layer on a first surface of said quantum well;        a second layer consisting of undoped gallium nitride on a second surface of said quantum well opposite said first surface;        ohmic contacts in a vertical geometry orientation;        a doped layer of gallium nitride between said buffer and said first undoped gallium nitride layer;        an undoped layer of aluminum gallium nitride on the surface of said second undoped gallium nitride layer on said quantum well that is opposite from said substrate and buffer; and        a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.     
     
     
       16. A light emitting diode according to  claim 15  further comprising:
   an ohmic contact on one surface of said light emitting diode; and    
   another ohmic contact on the opposite surface of said light emitting diode and with said ohmic contacts in a vertical geometry orientation.   
 
     
     
       17. A light emitting diode according to  claim 16  and further comprising:
   a conductive silicon carbide substrate; and    
   a conductive buffer layer between said substrate and said quantum well, with said doped gallium nitride layer on said buffer layer.   
 
     
     
       18. A light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
   an InGaN quantum well;        a first undoped gallium nitride layer on a first surface of said quantum well;        a second undoped gallium nitride layer directly on a second surface of said quantum well opposite said first surface;        an undoped layer of aluminum gallium nitride directly on the surface of said second undoped gallium nitride layer; and        a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.     
     
     
       19. A light emitting diode according to  claim 18  comprising a doped gallium nitride layer on said doped aluminum gallium nitride layer. 
     
     
       20. A light emitting diode according to  claim 18  wherein said first undoped gallium nitride layer is n- type and said doped layer of aluminum gallium nitride is p - type.   
     
     
       21. A light emitting diode according to  claim 18  wherein said quantum well comprises multiple quantum wells. 
     
     
       22. A light emitting diode according to  claim 18  further comprising:
   an ohmic contact on one surface of said light emitting diode; and    
   another ohmic contact on the opposite surface of said light emitting diode and with said ohmic contacts in a vertical geometry orientation.   
 
     
     
       23. A vertical geometry light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
   an InGaN quantum well;        a respective undoped gallium nitride layer directly on each surface of said quantum well;        ohmic contacts in a vertical geometry orientation;        a doped layer of gallium nitride below one of said undoped gallium nitride layers;        an undoped layer of aluminum gallium nitride directly on the surface of the opposite undoped gallium nitride layer; and        a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.     
     
     
       24. A light emitting diode according to  claim 23  comprising a doped gallium nitride layer on said doped aluminum gallium nitride layer. 
     
     
       25. A light emitting diode according to  claim 23  wherein:
   said opposite undoped gallium nitride layer is n - type; and    
   said doped layer of aluminum gallium nitride is p - type.   
 
     
     
       26. A light emitting diode according to  claim 23  wherein said quantum well comprises multiple quantum wells. 
     
     
       27. A light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
   a substrate;        an InGaN quantum well;        a buffer layer between said substrate and said quantum well;        a first undoped gallium nitride layer on a first surface of said quantum well;        a second undoped gallium nitride layer directly on a second surface of said quantum well opposite said first surface; and        a doped layer of gallium nitride between said buffer and said first undoped gallium nitride layer;        an undoped layer of aluminum gallium nitride directly on said second undoped gallium nitride layer; and        a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.     
     
     
       28. A light emitting diode according to  claim 27  wherein said substrate is a conductive silicon carbide substrate and said buffer layer is a conductive buffer layer between said substrate and said quantum well, with said doped gallium nitride layer on said buffer layer. 
     
     
       29. A light emitting diode according to  claim 27  further comprising:
   an ohmic contact on one surface of said light emitting diode; and    
   another ohmic contact on the opposite surface of said light emitting diode and with said ohmic contacts in a vertical geometry orientation.   
 
     
     
       30. A light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
   a substrate;        an InGaN quantum well;        a buffer layer between said substrate and said quantum well;        a first undoped gallium nitride layer on a first surface of said quantum well;        a second undoped gallium nitride directly on a second surface of said quantum well opposite said first surface;        ohmic contacts in a vertical geometry orientation;        a doped layer of gallium nitride between said buffer and said first undoped gallium nitride layer;        an undoped layer of aluminum gallium nitride directly on said second undoped gallium nitride layer; and        a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.     
     
     
       31. A light emitting diode according to  claim 30  wherein said substrate is a conductive silicon carbide substrate and said buffer layer is a conductive buffer layer between said substrate and said quantum well, with said doped gallium nitride layer on said buffer layer.