Electron emitters with dopant gradient

Abstract

Electron emitters and a method of fabricating emitters are disclosed, having a concentration gradient of impurities, such that the highest concentration of impurities is at the apex of the emitter tips and decreases toward the base of the emitter tips. The method comprises the steps of doping, patterning, etching, and oxidizing the substrate, thereby forming the emitter tips having impurity gradients.

1 . An in-process field emission device, comprising: 
 a substrate; and    a stalk extending from the substrate, further comprising: 
 an emitter having: 
 an apex, and  
 a base, and  
 
 an oxide around the emitter, wherein the oxide has a plurality of thicknesses, including: 
 a first thickness at the base, and  
 a greater second thickness at the apex.  
 
   
   
   
       2 . The in-process field emission device in  claim 1 , wherein the oxide has a third thickness above the apex greater than the second thickness.  
   
   
       3 . The in-process field emission device in  claim 2 , wherein the oxide covers the substrate.  
   
   
       4 . The in-process field emission device in  claim 3 , further comprising a dopant exclusively within the stalk, and having a plurality of concentrations that is generally directly proportional to the plurality of the thicknesses of the oxide.