Semiconductor device and method for manufacturing same

Abstract

There are provided a semiconductor device that includes a bypass protection unit against surge voltage or the like, achieves good withstand voltage characteristics and low on-resistance (low On-state voltage), has a simple structure, and is used for large-current purpose and a method for producing the semiconductor device. In the present invention, the semiconductor device includes an n + -type GaN substrate 1 having a GaN layer that is in ohmic contact with a supporting substrate, a FET having an n − -type GaN drift layer 2 in a first region R 1 , and an SBD having an anode electrode in a second region R 2 , the anode electrode being in Schottky contact with the n − -type GaN drift layer 2 . The FET and the SBD are arranged in parallel. A drain electrode D of the FET and a cathode electrode C of the SBD are formed on the back of the n + -type GaN substrate 1.

1 .- 6 . (canceled) 
     
     
         7 . A method for producing a semiconductor device comprising:
 a step of preparing a GaN substrate having a GaN layer that is in ohmic contact with a supporting substrate;   a step of forming an epitaxial layered body of first conductivity type GaN-based drift layer/second conductivity type GaN-based layer/first conductivity type GaN-based cap layer on the GaN substrate;   a step of etching the epitaxial layered body on the GaN substrate in a first region to form a FET opening that reaches the first conductivity type GaN-based drift layer;   a step of forming a channel-forming layer on an inside surface of the opening; and   a step of etching the channel-forming layer and the epitaxial layered body in a second region by masking the first region with a resist film to form an SBD opening that reaches the first conductivity type GaN-based drift layer,   wherein an electrode is formed so as to be in Schottky contact with the first conductivity type GaN-based drift layer in the SBD opening and contact the second conductivity type GaN-based layer in the opening.   
     
     
         8 . (canceled) 
     
     
         9 . The semiconductor device according to claim  1 , wherein the electrode that is in Schottky contact is located so as to fill the opening in the first conductivity type drift layer and the second conductivity type layer and extend onto the second conductivity type layer in the periphery of the opening. 
     
     
         10 . The method for producing the semiconductor device according to  claim 7 , in the step of forming the SBD opening and the step of forming the electrode, a bigger opening than the opening formed in the first conductivity type GaN-based drift layer is formed in the second conductivity type GaN-based layer, and the electrode that is in Schottky contact is formed so as to extend onto the second conductivity type GaN-based layer in the periphery of the opening in the first conductivity type GaN-based drift layer.