Nitride uv light sensors on silicon substrates

Abstract

An ultraviolet light sensor and method of manufacturing thereof are disclosed. The ultraviolet light sensor includes Group-III Nitride layers adjacent to a silicon wafer with one of the layers at least partially exposed such that a surface thereof can receive UV light to be detected. The Group-III Nitride layers include a p-type layer and an n-type layer, with p/n junctions therebetween forming at least one diode. Conductive contacts are arranged to conduct electrical current through the sensor as a function of ultraviolet light received at the outer Group-III Nitride layer. The Group-III Nitride layers may be formed from, e.g., GaN, InGaN, AlGaN, or InAlN. The sensor may include a buffer layer between one of the Group-III Nitride layers and the silicon wafer. By utilizing silicon as the substrate on which the UV sensor diode is formed, a UV sensor can be produced that is small, efficient, cost-effective, and compatible with other semiconductor circuits and processes. The sensor may be configured to be sensitive to a specific subtype or subband of ultraviolet radiation to be detected by selecting a specific composition of said Group-III Nitride layers.

1 . A method for manufacturing an ultraviolet light sensor, comprising:
 forming Group-III Nitride layers adjacent to a silicon wafer such that one of said Group-III Nitride layers is at least partially exposed, whereby said one of said Group-III Nitride layers can receive ultraviolet light to be detected, said Group-III Nitride layers comprising a p-type layer and an n-type layer with p/n junctions therebetween forming at least one diode; and   forming first and second conductive contacts such that said contacts conduct electrical current as a function of ultraviolet light received in at least one of said Group-III Nitride layers.   
     
     
         2 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming Group-III Nitride layers comprises selectively adjusting a band gap to be sensitive to a specific subtype or subband of ultraviolet radiation to be detected by selecting a specific composition of said Group-III Nitride layers. 
     
     
         3 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of selectively adjusting a band gap comprises selectively adjusting a band gap to be sensitive to UVA radiation. 
     
     
         4 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of selectively adjusting a band gap comprises selectively adjusting a band gap to be sensitive to UVB radiation. 
     
     
         5 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of selectively adjusting a band gap comprises selectively adjusting a band gap to be sensitive to UVC radiation. 
     
     
         6 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming first and second conductive contacts comprises forming such contacts on at least a portion of opposing outside surfaces. 
     
     
         7 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming Group-III Nitride layers comprises forming an n-type GaN layer on a buffer layer. 
     
     
         8 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming Group-III Nitride layers comprises growing a Group-III Nitride layer. 
     
     
         9 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming Group-III Nitride layers comprises depositing said Group-III Nitride layer by molecular beam epitaxy. 
     
     
         10 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming Group-III Nitride layers comprises depositing at least one Group-III Nitride layer by metal-organic chemical vapor deposition. 
     
     
         11 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming Group-III Nitride layers comprises depositing at least one Group-III Nitride layer by hydride vapor phase epitaxy. 
     
     
         12 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming Group-III Nitride layers comprises depositing at least one Group-III Nitride layer by remote plasma chemical vapor deposition. 
     
     
         13 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said step of forming first and second conductive contacts comprises forming at least one of said contacts as a grid so as to allow ultraviolet radiation to travel past said at least one contact to a top layer of said Group-III Nitride layers. 
     
     
         14 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said silicon wafer is of a material other than silicon carbide. 
     
     
         15 . The method for manufacturing an ultraviolet light sensor according to  claim 1 , wherein said one of said Group-III Nitride layers is at least partially exposed such that a top surface thereof can receive ultraviolet light to be detected by the ultraviolet light sensor. 
     
     
         16 . The method for manufacturing an ultraviolet light sensor according to  claim 15 , further comprising forming a filter in direct contact with the top surface, wherein the filter is a nitride layer that only allows a subband of ultraviolet light to pass through. 
     
     
         17 . The method for manufacturing an ultraviolet light sensor according to  claim 16 , further comprising forming a buffer layer between one of said Group-III Nitride layers and said silicon wafer. 
     
     
         18 . The method for manufacturing an ultraviolet light sensor according to  claim 17 , wherein said buffer layer comprises nitride.