Semiconductor device, manufacturing method and transistor circuit

Abstract

A transistor circuit includes a first high electron mobility transistor and a second high electron mobility transistor having a negative threshold voltage, wherein a source of the second high electron mobility transistor is coupled to a gate of the first high electron mobility transistor, and a gate of the second high electron mobility transistor is coupled to a source of the first high electron mobility transistor.

What is claimed is: 
     
         1 . A semiconductor device comprising:
 a first compound semiconductor film;   a laminated film in which a second compound semiconductor film and an insulating film are laminated and   an electrode including a first portion embedded in a recess formed on the laminated film and a second portion extending on both the first portion and the insulating film,   wherein the first portion includes a first embedded portion including a first length in an extending direction of the second portion and a second embedded portion disposed between the first embedded portion and a bottom of the recess with a second length smaller than the first length.   
     
     
         2 . The semiconductor device according to  claim 1 ,
 wherein the recess reaches inside the second compound semiconductor film.   
     
     
         3 . The semiconductor device according to  claim 1 ,
 wherein the recess reaches a surface of the second compound semiconductor film or is stopped inside the first insulating film.   
     
     
         4 . The semiconductor device according to  claim 1 ,
 wherein an insulating layer is provided between the electrode and the laminated film.   
     
     
         5 . The semiconductor device according to  claim 1 ,
 wherein the second portion expands to both sides of the first portion, and   the first embedded portion expands to both sides of the second embedded portion.   
     
     
         6 . The semiconductor device according to  claim 1 ,
 wherein the semiconductor device is a high electron mobility transistor,   the first compound semiconductor film is a channel layer of the high electron mobility transistor,   the second compound semiconductor film is a barrier layer of the high electron mobility transistor,   the electrode is an electrode in which a gate and two field plates are combined, and   the extending direction is a direction from the source toward the drain of the high electron mobility transistor.