Semiconductor device

Abstract

A semiconductor device comprising: a Metal Oxide Semiconductor Field Effect Transistor including: a semiconductor substrate including a first semiconductor layer of a first conductivity type; second semiconductor layers of a second conductivity type extending in a depth direction from one surface of the semiconductor substrate, and having space each other; a first diode including a fifth semiconductor layer of the second conductivity type contacting the second semiconductor layer in one surface side of the semiconductor substrate, the first semiconductor layer and the second semiconductor layers; and an anode of the second diode connected to an anode of the first diode.

What is claimed is: 
     
         1 . A semiconductor device comprising:
 a Metal Oxide Semiconductor Field Effect Transistor including:
 a semiconductor substrate including a first semiconductor layer of a first conductivity type; 
 second semiconductor layers of a second conductivity type extending in a depth direction from one surface of the semiconductor substrate, and having space each other; 
 third semiconductor layers of the second conductivity type formed on at least of the second semiconductor layers in one surface side of the semiconductor substrate; 
 fourth semiconductor layers of the first conductivity type partially formed on a surface of the third semiconductor layers; 
 each of control electrodes formed on a surface of the third semiconductor layer via an insulating film; 
 a first electrode connected the third semiconductor layers and the fourth semiconductor layers; and 
 a second electrode electrically connected on the other surface of the first semiconductor layer; 
   a first diode including the first semiconductor layer, the second semiconductor layers and a fifth semiconductor layer of the second conductivity type formed in the semiconductor substrate; and   a cathode of a second diode including a seventh semiconductor layer connected to the control electrode, and an anode of the second diode connected to an anode of the first diode.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the breakdown voltage of the first diode is lower than the breakdown voltage of the Metal Oxide Semiconductor Field Effect Transistor. 
     
     
         3 . The semiconductor device according to  claim 1 , further comprising extracting electrode for the control electrode is formed to a part of the first electrode, and the first diode and the second diode are formed under the extracting electrode. 
     
     
         4 . The semiconductor device according to  claim 1 , wherein a space between the fifth semiconductor layers is wider than a space between the third semiconductor layers. 
     
     
         5 . The semiconductor device according to  claim 1 , wherein a space between the second semiconductor layers on the first diode side is wider than a space between the second semiconductor layers on the Metal Oxide Semiconductor Field Effect Transistor side. 
     
     
         6 . The semiconductor device according to  claim 1 , wherein an impurity concentration of each of the second semiconductor layers increases according the direction from the second electrode side to the first electrode side. 
     
     
         7 . The semiconductor device according to  claim 1 , wherein an impurity concentration of each of the second semiconductor layers highly changes at the first diode side than the Metal Oxide Semiconductor Field Effect Transistor side. 
     
     
         8 . The semiconductor device according to  claim 1 , wherein an impurity concentration of the second semiconductor layer is higher than an impurity concentration of the first semiconductor layer in the first diode side, and the impurity concentration of the second semiconductor layer is lower than the impurity concentration of the first semiconductor layer in the Metal Oxide Semiconductor Field Effect Transistor side. 
     
     
         9 . The semiconductor device according to  claim 1 , wherein an impurity concentration of the first semiconductor layer and the second semiconductor layer is higher in the first diode side than in the Metal Oxide Semiconductor Field Effect Transistor side. 
     
     
         10 . The semiconductor device according to  claim 1 , wherein the second diode is Schottky barrier diode. 
     
     
         11 . The semiconductor device according to  claim 1 , wherein the second diode is p-intrinsic-n diode. 
     
     
         12 . The semiconductor device according to  claim 1 , wherein the second diode is made from polysilicon. 
     
     
         13 . The semiconductor device according to  claim 1 , wherein the breakdown voltage between the second electrode and the first electrode is higher than the breakdown voltage between the connecting junction and the first electrode. 
     
     
         14 . The semiconductor device according to  claim 1 , wherein the breakdown voltage of the second diode is higher than an applied compensating voltage between the control electrode and the second electrode. 
     
     
         15 . The semiconductor device according to  claim 1 , wherein the avalanche breakdown in the first diode arise a voltage drop at the gate resistance so as to be able to operate the Metal Oxide Semiconductor Field Effect Transistor. 
     
     
         16 . A semiconductor device comprising:
 a Metal Oxide Semiconductor Field Effect Transistor including:
 a semiconductor substrate including a first semiconductor layer of a first conductivity type; 
 trenches extending in a depth direction from one surface of the semiconductor substrate, and having space each other; 
 implanting electrode formed in second main electrode side of the trenches via gate insulating film; 
 control electrode formed in first electrode side of the trenches via gate insulating film; 
 third semiconductor layers of the second conductivity type formed in one surface side of the semiconductor substrate; 
 fourth semiconductor layers of the first conductivity type partially formed on a surface of the third semiconductor layers; 
 a first electrode connected the third semiconductor layers and the fourth semiconductor layers; and 
 a second electrode electrically connected on the other surface of the first semiconductor layer; 
   a first diode including the first semiconductor layer and a fifth semiconductor layer of the second conductivity type formed in the semiconductor substrate; and   a cathode of a second diode including a seventh semiconductor layer connected to the control electrode, and an anode of the second diode connected to an anode of the first diode.   
     
     
         17 . The semiconductor device according to  claim 16 , wherein space between the trenches of the first diode side is wider than the space between the trenches of the Metal Oxide Semiconductor Field Effect Transistor side.