Enhancement Mode III-Nitride Device

Abstract

A III-nitride switch includes a recessed gate contact to produce a nominally off, or an enhancement mode, device. By providing a recessed gate contact, a conduction channel formed at the interface of two III-nitride materials is interrupted when the gate electrode is inactive to prevent current flow in the device. The gate electrode can be a schottky contact or an insulated metal contact. Two gate electrodes can be provided to form a bi-directional switch with nominally off characteristics. The recesses formed with the gate electrode can have sloped sides. The gate electrodes can be formed in a number of geometries in conjunction with current carrying electrodes of the device.

1 - 19 . (canceled) 
     
     
         20 - 29 . (canceled) 
     
     
         30 . A method of fabricating a III-nitride device, comprising:
 forming a conduction channel at a III-nitride heterojunction between first and second III-nitride bodies, the conduction channel including a two-dimensional electron gas;   forming a modified region in said first III-nitride body, the modified region causing an altered region in the conduction channel;   disposing a gate electrode over said altered region, said gate electrode operable to selectively permit and prevent current conduction in said conduction channel.   
     
     
         31 . The method of  claim 30 , wherein forming said modified region comprises introducing dopants into a region of said first III-nitride body. 
     
     
         32 . The method of  claim 30 , wherein forming said modified region comprises diffusing dopants into a region of said first III-nitride body. 
     
     
         33 . The method of  claim 30 , wherein forming said modified region comprises oxidizing a region of said first III-nitride body. 
     
     
         34 . The method of  claim 30 , wherein forming said modified region comprises nitridizing a region of said first III-nitride body. 
     
     
         35 . The method of  claim 30 , comprising forming a recess in said first III-nitride body, said gate electrode formed in said recess. 
     
     
         36 . The method of  claim 30 , wherein said III-nitride device comprises an enhancement mode device. 
     
     
         37 . The method of  claim 30 , wherein said first II nitride body comprises AlGaN and said second III-nitride body comprises GaN. 
     
     
         38 . The method of  claim 30 , wherein forming said conduction channel at said III-nitride heterojunction comprises forming said first III-nitride body on said second III-nitride body, wherein said first and second III-nitride bodies comprise undoped III-nitride bodies. 
     
     
         39 . The method of  claim 30 , wherein forming said modified region comprises forming an oxidized region in a top surface of said first III-nitride body. 
     
     
         40 . The method of  claim 39 , wherein said first III-nitride body is an AlGaN layer and said oxidized region is in said AlGaN layer. 
     
     
         41 . The method of  claim 30 , wherein forming said modified region comprises forming an oxidized region below said gate electrode. 
     
     
         42 . The method of  claim 41 , wherein said gate electrode is directly on said oxidized region. 
     
     
         43 . The method of  claim 30 , wherein forming said modified region comprises forming an oxidized region recessed below a top surface of said first III-nitride body. 
     
     
         44 . The method of  claim 30 , wherein forming said modified region comprises forming an oxidized region on sidewalls of a recess in said first III-nitride body. 
     
     
         45 . The method of  claim 44 , wherein a portion of said oxidized region tapers into said first III-nitride body.