Gan-based schottky barrier diode with field plate

Abstract

A method for fabricating a III-nitride semiconductor device includes providing a III-nitride substrate having a first surface and a second surface opposing the first surface, forming a III-nitride epitaxial layer coupled to the first surface of the III-nitride substrate, and removing at least a portion of the III-nitride epitaxial layer to form a first exposed surface. The method further includes forming a dielectric layer coupled to the first exposed surface, removing at least a portion of the dielectric layer, and forming a metallic layer coupled to a remaining portion of the dielectric layer such that the remaining portion of the dielectric layer is disposed between the III-nitride epitaxial layer and the metallic layer.

What is claimed is: 
     
         1 . A method for fabricating a gallium nitride (GaN) Schottky diode, the method comprising:
 providing an n-type GaN substrate having a first surface and a second surface opposing the first surface;   forming an n-type GaN epitaxial layer coupled to the first surface of the n-type GaN substrate;   removing at least a portion of the n-type GaN epitaxial layer to form a first exposed surface;   forming a dielectric layer coupled to the first exposed surface, the dielectric layer formed using spin coating;   removing at least a portion of the dielectric layer; and   forming a Schottky metal structure coupled to a portion of the n-type GaN epitaxial layer and a remaining portion of the dielectric layer such that:
 the remaining portion of the dielectric layer is disposed between the n-type GaN epitaxial layer and the Schottky metal structure; and 
 the Schottky metal structure forms a Schottky barrier with the portion of the n-type GaN epitaxial layer. 
   
     
     
         2 . The method of  claim 1  wherein removing at least a portion of the n-type GaN epitaxial layer comprises forming a second exposed surface angled with respect to the first exposed surface. 
     
     
         3 . The method of  claim 1  wherein removing at least a portion of the dielectric layer comprises forming a first surface of the dielectric layer that is angled with respect to a second surface of the dielectric layer. 
     
     
         4 . The method of  claim 3  wherein the first surface has a varying slope with respect to the second surface. 
     
     
         5 . A method for fabricating a III-nitride semiconductor device, the method comprising:
 providing a III-nitride substrate having a first surface and a second surface opposing the first surface;   forming a III-nitride epitaxial layer coupled to the first surface of the III-nitride substrate;   removing at least a portion of the III-nitride epitaxial layer to form a first exposed surface;   forming a dielectric layer coupled to the first exposed surface;   removing at least a portion of the dielectric layer; and   forming a metallic layer coupled to a remaining portion of the dielectric layer such that the remaining portion of the dielectric layer is disposed between the III-nitride epitaxial layer and the metallic layer.   
     
     
         6 . The method of  claim 5  wherein forming the dielectric layer comprises using a spin-coating technique. 
     
     
         7 . The method of  claim 5  wherein removing at least a portion of the III-nitride epitaxial layer comprises forming a second exposed surface angled with respect to the first exposed surface. 
     
     
         8 . The method of  claim 7  wherein an angle between the first exposed surface and the second exposed surface is between 45° and 90°. 
     
     
         9 . The method of  claim 5  wherein removing at least a portion of the dielectric layer comprises forming a first surface of the dielectric layer that is angled with respect to a second surface of the dielectric layer. 
     
     
         10 . The method of  claim 9  wherein an angle between the first surface of the dielectric layer and the second surface of the dielectric layer is less than 45°. 
     
     
         11 . The method of  claim 9  wherein the first surface has a varying slope with respect to the second surface. 
     
     
         12 . The method of  claim 5  wherein forming the metallic layer further includes forming a Schottky metal structure coupled to a portion of the III-nitride epitaxial layer, the Schottky metal structure forming a Schottky barrier with the portion of the III-nitride epitaxial layer. 
     
     
         13 . The method of  claim 5  wherein the dielectric layer includes at least one of benzocyclobutene (BCB) or spin-on glass (SOG).