Electric field management for a group iii-nitride semiconductor device

Abstract

A semiconductor device includes a substrate, a first active layer, a second active layer, at least first and second electrodes, an E-field management layer, and at least one injection electrode. The first active layer is disposed over the substrate. The second active layer is disposed on the first active layer such that a laterally extending conductive channel arises which extends in a lateral direction. The laterally extending conductive channel is located between the first active layer and the second active layer. The first and second electrodes are electrically connected to the first active layer. The E-field management layer, which reduces the electric-field gradients arising in the first and second active layers, is disposed over the second active layer. The injection electrode is electrically connected to the E-field management layer.

What is claimed is: 
     
         1 . A semiconductor device, comprising:
 a substrate;   a first active layer disposed over the substrate;   a second active layer disposed on the first active layer such that a laterally extending conductive channel arises which extends in a lateral direction, the laterally extending conductive channel being located between the first active layer and the second active layer;   first and second electrodes electrically connected to the first active layer; and   an E-field management layer for reducing electric-field gradients arising in the first and second active layers, the E-field management layer being disposed over the second active layer, the E-field management layer having a resistivity greater than 1 kΩ×cm; and   an injection electrode electrically connected to the E-field management layer.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the E-field management layer comprises an intrinsic material or a material that includes therein impurities and/or defects that give rise to the resistivity, a concentration of the impurities being uniform in a lateral direction between the injection electrode and the second electrode. 
     
     
         3 . The semiconductor device according to  claim 1 , wherein the E-field management layer comprises an intrinsic material or a material that includes therein impurities and/or defects that give rise to the resistivity, a concentration of the impurities being non-uniform in a lateral direction between the injection electrode and the second electrode. 
     
     
         4 . The semiconductor device according to  claim 1 , wherein the E-field management layer comprises an intrinsic material or a material that includes therein impurities and/or defects that give rise to the resistivity, a concentration of the impurities being uniform in a vertical direction through the E-field management layer. 
     
     
         5 . The semiconductor device according to  claim 1 , wherein the E-field management layer comprises an intrinsic material or a material that includes therein impurities and/or defects that give rise to the resistivity, a concentration of the impurities being non-uniform in a vertical direction through the E-field management layer. 
     
     
         6 . The semiconductor device according to  claim 1 , further comprising an etch stop layer disposed between the second active layer and the E-field management layer, the etch stop layer being etch resistant to etching of the E-field management layer. 
     
     
         7 . The semiconductor device according to  claim 1 , further comprising a carrier doping layer disposed between the second active layer and the E-field management layer. 
     
     
         8 . The semiconductor device according to  claim 6 , further comprising a carrier doping layer disposed on the etch stop layer. 
     
     
         9 . The semiconductor device according to  claim 1 , wherein the first and second electrodes are source and drain electrodes, respectively, and further comprising a gate electrode disposed between the source electrode and the drain electrode, wherein the injection electrode is disposed between the gate electrode and the drain electrode, the gate electrode being disposed in a recess extending into the E-field management layer. 
     
     
         10 . The semiconductor device according to  claim 1 , wherein the first and second electrodes are source and drain electrodes, respectively, and further comprising a gate electrode disposed between the source electrode and the drain electrode, wherein the injection electrode is disposed between the gate electrode and the drain electrode, the injection electrode and the source electrode or the gate electrode being configured such that they are maintained at a common electrical potential. 
     
     
         11 . The semiconductor device according to  claim 1 , wherein the first and second electrodes are source and drain electrodes, respectively, and further comprising a gate electrode disposed between the source electrode and the drain electrode, wherein the injection electrode is disposed between the gate electrode and the drain electrode, the injection electrode and the source electrode or the gate electrode being configured such that they are maintained at different electrical potentials. 
     
     
         12 . The semiconductor device according to  claim 1 , wherein the first and second electrodes are source and drain electrodes, respectively, and further comprising a gate electrode disposed between the source electrode and the drain electrode, wherein the injection electrode is disposed between the gate electrode and the drain electrode, the drain electrode and the E-field management layer being electrically isolated from one another 
     
     
         13 . The semiconductor device according to  claim 1 , wherein the first and second electrodes are an anode and a cathode, respectively, wherein the injection electrode is disposed between the anode and the cathode. 
     
     
         14 . The semiconductor device of  claim 1 , where the at least one injection electrode comprises a plurality of injection electrodes electrically connected to the E-field management layer. 
     
     
         15 . The semiconductor device according to  claim 1 , wherein the second active layer comprises a plurality of sublayers, at least one of the plurality of sublayers having a wider band gap than the first active layer. 
     
     
         16 . The semiconductor device according to  claim 1 , wherein the E-field management layer includes impurities selected from the group consisting of carbon, iron, magnesium and zinc.