III-Nitride Device with Improved Transconductance

Abstract

A III-Nitride device has a back-gate disposed in a trench and under and in close proximity to the 2 DEG layer and in lateral alignment with the main gate of the device. A laterally disposed trench is also disposed in a trench and under and in close proximity to the drift region between the gate and drain electrodes of the device. The back-gate is connected to the main gate and the field plate is connected to the source electrode. The back-gate can consist of a highly conductive silicon substrate.

1 - 30 . (canceled) 
     
     
         31 . A III-Nitride device having improved transconductance, said device comprising:
 a substrate;   a first III-nitride layer supported by said substrate;   a second III-Nitride layer atop said first III-Nitride layer and creating a 2DEG conducting layer at the interface of said first and second III-Nitride layers;   first and second spaced main electrodes connected to said second III-Nitride layer;   a main gate structure connected to said second III-Nitride layer and disposed laterally between said first and second main electrodes and adapted to adjustably change the conductivity of said 2DEG layer beneath said main gate structure in response to a predetermined signal on said main gate structure;   a back-gate structure having a lateral position in alignment with a lateral position of said main gate structure and beneath said 2DEG layer;   said back-gate structure electrically connected to a potential of said main gate structure;   said back-gate structure disposed within a trench without exposing said first III-Nitride layer, wherein a web portion of said substrate is disposed between a bottom surface of said trench and said first III-Nitride layer.   
     
     
         32 . The III-Nitride device of  claim 31 , wherein a bottom of said trench is disposed near said first III-Nitride layer. 
     
     
         33 . The III-Nitride device of  claim 31 , wherein a bottom of said trench is disposed near said 2DEG layer. 
     
     
         34 . The III-Nitride device of  claim 31 , further comprising a transition layer disposed between said substrate and said first III-Nitride layer. 
     
     
         35 . The III-Nitride device of  claim 31 , wherein said first and second III-Nitride layers comprise a GaN layer and an AlGaN layer respectively. 
     
     
         36 . The III-Nitride device of  claim 31 , wherein said first and second electrodes comprise source and drain electrodes respectively. 
     
     
         37 . The III-Nitride device of  claim 31 , wherein said main gate structure comprises a gate dielectric layer on said second III-Nitride layer and a conductive gate layer atop said dielectric layer. 
     
     
         38 . The III-Nitride device of  claim 31 , wherein said main gate structure comprises a Schottky gate on said second III-Nitride layer. 
     
     
         39 . A III-Nitride device having improved transconductance, said device comprising:
 a substrate;   a first III-nitride layer supported by said substrate;   a second III-Nitride layer atop said first III-Nitride layer and creating a 2DEG conducting layer at the interface of said first and second III-Nitride layers;   first and second spaced main electrodes connected to said second III-Nitride layer;   a main gate structure connected to said second III-Nitride layer and disposed laterally between said first and second main electrodes and adapted to adjustably change the conductivity of said 2DEG layer beneath said main gate structure in response to a predetermined signal on said main gate structure;   a back-gate structure having a lateral position in alignment with a lateral position of said main gate structure and beneath said 2DEG layer;   said lateral position of said back-gate structure not overlapping with a lateral position of said first main electrode and a lateral position of said second main electrode;   said back-gate structure electrically connected to a potential of said main gate structure;   wherein said first III-Nitride layer of said III-Nitride device is not exposed.   
     
     
         40 . The III-Nitride device of  claim 39 , further comprising a transition layer disposed between said substrate and said first III-Nitride layer. 
     
     
         41 . The III-Nitride device of  claim 39 , wherein said first and second III-Nitride layers comprise a GaN layer and an AlGaN layer respectively. 
     
     
         42 . The III-Nitride device of  claim 39 , wherein said first and second electrodes comprise source and drain electrodes respectively. 
     
     
         43 . The III-Nitride device of  claim 39 , wherein said main gate structure comprises a gate dielectric layer on said second III-Nitride layer and a conductive gate layer atop said dielectric layer. 
     
     
         44 . The III-Nitride device of  claim 39 , wherein said main gate structure comprises a Schottky gate on said second III-Nitride layer.