Uv light emitting devices and systems and methods for production

Abstract

A method of fabricating an ultraviolet (UV) light emitting device includes receiving a UV transmissive substrate, forming a first UV transmissive layer comprising aluminum nitride upon the UV transmissive substrate using a first deposition technique at a temperature less than about 800 degrees Celsius or greater than about 1200 degrees Celsius, forming a second UV transmissive layer comprising aluminum nitride upon the first UV transmissive layer comprising aluminum nitride using a second deposition technique that is different from the first deposition technique, at a temperature within a range of about 800 degrees Celsius to about 1200 degrees Celsius, forming an n-type layer comprising aluminum gallium nitride layer upon the second UV transmissive layer, forming one or more quantum well structures comprising aluminum gallium nitride upon the n-type layer, and forming a p-type nitride layer upon the one or more quantum well structures.

What is claimed is: 
     
         1 . A method of fabricating an ultraviolet (UV) light emitting device comprising:
 receiving a UV transmissive substrate;   forming a UV transmissive layer upon the UV transmissive substrate, comprising:
 forming a first UV transmissive layer comprising aluminum nitride upon the UV transmissive substrate using a first deposition technique at a temperature less than about 800 degrees Celsius or greater than about 1200 degrees Celsius; and 
 forming a second UV transmissive layer comprising aluminum nitride upon the first UV transmissive layer comprising aluminum nitride using a second deposition technique that is different from the first deposition technique, at a temperature within a range of about 800 degrees Celsius to about 1200 degrees Celsius; and 
   forming a UV light emitting layer structure on the UV transmissive layer, comprising:
 forming an n-type layer comprising aluminum gallium nitride layer upon the UV transmissive layer; 
 forming one or more quantum well structures comprising aluminum gallium nitride upon the n-type layer; and 
 forming a p-type nitride layer upon the one or more quantum well structures. 
   
     
     
         2 . The method of  claim 1  wherein the UV transmissive layer has a thickness within a range of about 10 nm to about 3 microns. 
     
     
         3 . The method of  claim 1  wherein the UV transmissive layer has a thickness of about 3 microns to 10 microns. 
     
     
         4 . The method of  claim 1  wherein the UV transmissive layer has transmissivity in the UV wavelength range within a transmissivity range of about 50% to about 99%. 
     
     
         5 . The method of  claim 1  wherein the method of forming the first UV transmissive layer uses a deposition process selected from a group consisting of: hydride vapor phase epitaxy, atomic layer deposition, liquid phase epitaxy, physical vapor deposition, sputtering, solid source solution epitaxy. 
     
     
         6 . The method of  claim 1  wherein the method of forming the second UV transmissive layer uses a deposition process selected from a group consisting of: metalorganic chemical vapor deposition, metalorganic vapor phase epitaxy, molecular beam epitaxy, chemical beam epitaxy. 
     
     
         7 . The method of  claim 1   wherein the first UV transmissive layer comprises polycrystalline aluminum nitride; and   wherein the second UV transmissive layer comprises single crystal aluminum nitride.   
     
     
         8 . The method of  claim 1  wherein the receiving the UV transmissive substrate comprises receiving a substrate selected from a group consisting of: a quartz substrate, a sapphire substrate, and a free standing single crystal aluminum nitride substrate. 
     
     
         9 . An ultraviolet (UV) light emitting device comprising:
 a UV transmissive substrate;   a UV transmissive layer disposed upon the UV transmissive substrate, the UV transmissive layer comprising:
 a first UV transmissive layer comprising aluminum nitride disposed upon the UV transmissive substrate at a temperature less than about 800 degrees Celsius or greater than about 1200 degrees Celsius; and 
 a second UV transmissive layer comprising aluminum nitride disposed upon the first UV transmissive aluminum nitride material at a temperature within a range of about 800 degrees Celsius to about 1200 degrees Celsius; and 
   a UV light emitting structure disposed upon the UV transmissive layer, the UV light emitting layer structure comprising:
 an n-type layer comprising aluminum gallium nitride disposed upon the UV transmissive layer; 
 one or more quantum well structures disposed upon the n-type layer; and 
 a p-type layer comprising nitride material disposed upon the one or more quantum well structures. 
   
     
     
         10 . The UV device of  claim 9  wherein the UV transmissive layer has a thickness within a range within about 10 nm to about 3 microns. 
     
     
         11 . The UV device of  claim 9  wherein the UV transmissive layer has a thickness within a range within about 3 microns to about 10 microns. 
     
     
         12 . The UV device of  claim 9  wherein the UV transmissive layer has transmissivity in the UV wavelength range within a transmissivity range of about 50% to about 99%. 
     
     
         13 . The UV device of  claim 9   wherein the first UV transmissive layer comprises polycrystalline aluminum nitride; and   wherein the second UV transmissive layer comprises single crystal aluminum nitride.   
     
     
         14 . The UV device of  claim 9  wherein the UV transmissive substrate comprises a plurality of patterns that scatter strongly with short wavelength UV light. 
     
     
         15 . The UV device of  claim 14  wherein the patterns comprises geometric features within a height range of about 50 nm to about 500 nm. 
     
     
         16 . The UV device of  claim 9 , wherein UV transmissive substrate is selected from a group consisting of: quartz, sapphire, and free standing single crystal aluminum nitride. 
     
     
         17 . A multi-chambered deposition system comprising:
 a first chamber for depositing a first UV transmissive layer comprising aluminum nitride at temperature less than about 800 degrees Celsius or greater than about 1200 degrees Celsius; and   a second chamber for depositing a second UV transmissive layer comprising aluminum nitride at a temperature within a range of about 800 degrees Celsius to about 1200 degrees Celsius upon the first UV transmissive layer comprising aluminum nitride.   
     
     
         18 . The system of  claim 17  further comprising a third chamber for depositing an n-type layer comprising aluminum gallium nitride material upon the second UV transmissive layer. 
     
     
         19 . The system of  claim 18  wherein the third chamber is the second chamber. 
     
     
         20 . The system of  claim 17  wherein the first chamber comprises a chamber adapted to perform: hydride vapor phase epitaxy, atomic layer deposition, liquid phase epitaxy, physical vapor deposition, sputtering, or solid source solution growth. 
     
     
         21 . The system of  claim 17  wherein the second chamber comprises a chamber adapted to perform: metalorganic chemical vapor deposition, metalorganic vapour phase epitaxy, molecular beam epitaxy, or chemical beam epitaxy. 
     
     
         22 . The system of  claim 18  wherein the third chamber is also for depositing one or more quantum well structures comprising aluminum gallium nitride upon the n-type layer. 
     
     
         23 . The system of  claim 22  wherein the third chamber is also for depositing a p-type nitride layer upon the one or more quantum well structures. 
     
     
         24 . The system of  claim 22  further comprising a fourth chamber for depositing a p-type nitride layer upon the one or more quantum well structures. 
     
     
         25 . The system of  claim 18  further comprising a fourth chamber for depositing one or more quantum well structures comprising aluminum gallium nitride upon the n-type layer. 
     
     
         26 . The system of  claim 25  wherein the fourth chamber is also for depositing a p-type nitride layer upon the one or more quantum well structures. 
     
     
         27 . The system of  claim 25  further comprising a fifth chamber for depositing a p-type nitride layer upon the one or more quantum well structures. 
     
     
         28 . The system of  claim 17  further comprising a wafer handling portion coupled to the first chamber and the second chamber, wherein the wafer handling portion is configured to transfer the wafer between the first chamber and the second chamber under control of a processor. 
     
     
         29 . The system of  claim 17  further comprising a vacuum chamber coupled to the first chamber and the second chamber, wherein the vacuum chamber is configured to maintain the wafer under a vacuum when the wafer is transferred between the first chamber and the second chamber.