Gallium nitride based high electron mobility transistor including an aluminum gallium nitride barrier layer

Abstract

A semiconductor structure includes a III-nitride substrate with a first side and a second side opposing the first side. The III-nitride substrate is characterized by a first conductivity type and a first dopant concentration. The semiconductor structure also includes a III-nitride epitaxial layer of the first conductivity type coupled to the first surface of the III-nitride substrate, and a first metallic structure electrically coupled to the second surface of the III-nitride substrate. The semiconductor structure further includes an AlGaN epitaxial layer coupled to the III-nitride epitaxial layer of the first conductivity type, and a III-nitride epitaxial structure of a second conductivity type coupled to the AlGaN epitaxial layer. The III-nitride epitaxial structure comprises at least one edge termination structure.

What is claimed is: 
     
         1 . A III-nitride HEMT comprising:
 a substrate comprising a first n-type III-nitride material;   a drift region comprising a second n-type III-nitride material coupled to the substrate and disposed adjacent to the substrate along a vertical direction;   an AlGaN barrier layer coupled to the drift region;   a p-type III-nitride epitaxial layer coupled to the AlGaN barrier layer;   a Schottky contact coupled to the p-type III-nitride epitaxial layer; and   a plurality of electrical contacts coupled to the AlGaN drift region.   
     
     
         2 . The III-nitride HEMT of  claim 1  wherein the drift region has a thickness between 5 μm and 100 μm. 
     
     
         3 . The III-nitride HEMT of  claim 1  wherein the AlGaN barrier layer is characterized by a thickness ranging from 1 nm to 30 nm. 
     
     
         4 . The III-nitride HEMT of  claim 1  wherein the substrate comprises an n-type GaN substrate. 
     
     
         5 . The III-nitride HEMT of  claim 1  wherein the plurality of electrical contacts comprise an ohmic source contact and an ohmic drain contact. 
     
     
         6 . The III-nitride HEMT of  claim 5  wherein the ohmic source contact and the ohmic drain contact are separated along a horizontal direction. 
     
     
         7 . The III-nitride HEMT of  claim 1  wherein the AlGaN epitaxial layer is characterized by a dopant concentration of greater than 1×10 17  cm −3 . 
     
     
         8 . The III-nitride HEMT of  claim 1  wherein the AlGaN epitaxial layer is characterized by an aluminum mole fraction between 0.01 and 0.50. 
     
     
         9 . The III-nitride HEMT of  claim 1  wherein the first n-type III-nitride material comprises an n-type GaN substrate. 
     
     
         10 . The III-nitride HEMT of  claim 1  wherein the p-type III-nitride epitaxial layer comprises a p-type GaN layer.