Semiconductor device

Abstract

A semiconductor device protects against concentration of electric current at a front end portion of one of the electrodes thereof The semiconductor device includes a substrate, a compound semiconductor layer formed on the substrate and having a channel layer based on a hetero junction, a first main electrode formed on the compound semiconductor layer, a second main electrode formed on the compound semiconductor surrounding the first main electrode and having a linear region and an arc-shaped region, a control electrode formed on the compound semiconductor layer and disposed opposite to the first main electrode and the second main electrode, an electric current being made to flow between the first main electrode and the second main electrode, and an electric current limiting section formed between the first main electrode and the arc-shaped region of the second main electrode.

1 . A semiconductor device comprising:
 a substrate;   a compound semiconductor layer formed on the substrate and having a two-dimensional carrier gas layer based on a hetero-junction;   a first main electrode formed on the compound semiconductor layer;   a second main electrode formed on the compound semiconductor layer so as to surround the first main electrode in a plan view and having a linear region and an arc-shaped region;   a control electrode formed between the first main electrode and the second main electrode on the compound semiconductor layer;   an electric current being made to flow between the first main electrode and the second main electrode by way of the two-dimensional carrier gas layer; and   an electric current limiting section for limiting the electric current from flowing between the first main electrode and the arc-shaped region of the second main electrode.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the electric current limiting section is a part, where carrier concentration of the two-dimensional carrier gas layer formed between the first main electrode and the arc-shaped region of the second main electrode is partly reduced. 
     
     
         3 . The semiconductor device according to  claim 1 , wherein the electric current limiting section is a part, where carrier concentration of the two-dimensional carrier gas layer formed between the first main electrode and the arc-shaped region of the second main electrode right under the control electrode is partly reduced. 
     
     
         4 . The semiconductor device according to  claim 1 , wherein the electric current limiting section is a part, where the two-dimensional carrier gas layer is removed between the first main electrode and the arc-shaped region of the second main electrode. 
     
     
         5 . The semiconductor device according to  claim 1 , wherein the compound semiconductor layer includes a channel layer in which the two-dimensional carrier gas layer is formed, and a carrier supply layer formed on the channel layer to produce a hetero junction, and the electric current limiting section is a part between the first main electrode and the arc-shaped region of the second main electrode where the carrier supply layer is partly thinned. 
     
     
         6 . The semiconductor device according to  claim 1 , wherein the electric current limiting section is a part, where the compound semiconductor layer junctioned to the channel layer is doped with fluorine ions, between the first main electrode and the arc-shaped region of the second main electrode. 
     
     
         7 . The semiconductor device according to  claim 1 , wherein the electric current limiting section is a part, where p-type semiconductor layer is formed in the compound semiconductor layer junctioned to the channel layer between the first main electrode and the arc-shaped region of the second main electrode.