Silicon carbide semiconductor device, method of manufacturing silicon carbide semiconductor device and method of designing silicon carbide semiconductor device.

A method of manufacturing silicon carbide semiconductor device, comprising:

• a step of forming a silicon carbide layer of a first conductivity type;
• a step of forming a silicon carbide layer of a second conductivity type on the silicon carbide layer of the first conductivity type;
• a step of forming a gate trench that extends from a surface of the silicon carbide layer of the second conductivity type to such a depth that the gate trench reaches the silicon carbide layer of the first conductivity type;
• a step of forming a protection trench that extends from the surface of the silicon carbide layer of the second conductivity type to a depth greater than the depth of the gate trench;
• a step of providing a gate electrode in the gate trench with an insulating film interposed therebetween;
• and
• a step of providing a first conductive member in the protection trench,
• wherein a region in a horizontal direction that includes both the gate trench and a protection trench that surrounds only a part of the gate trench in the horizontal direction is a cell region,
• a region in the horizontal direction that includes a protection trench and in which a gate pad or a lead electrode connected to the gate pad is disposed is a gate region,
• a second conductive member is provided above a part of the gate trench in the cell region and in the gate region, and
• the second conductive member is disposed to extend from above the gate trench in the cell region to the gate region through above a part of the cell region in which the protection trench is not provided.

A method of designing a silicon carbide semiconductor device, wherein the silicon carbide semiconductor device comprises:

• a silicon carbide layer of a first conductivity type;
• a silicon carbide layer of a second conductivity type formed on the silicon carbide layer of the first conductivity type;
• a gate trench formed to extend from a surface of the silicon carbide layer of the second conductivity type to such a depth that the gate trench reaches the silicon carbide layer of the first conductivity type;
• a gate electrode provided in the gate trench with an insulating film interposed therebetween;
• a protection trench formed to extend from the surface of the silicon carbide layer of the second conductivity type to a depth greater than the depth of the gate trench;
• and
• a first conductive member provided in the protection trench,
• a region in a horizontal direction that includes both the gate trench and a protection trench that surrounds only a part of the gate trench in the horizontal direction is a cell region,
• a region in the horizontal direction that includes a protection trench and in which a gate pad or a lead electrode connected to the gate pad is disposed is a gate region,
• a second conductive member is provided above the gate trench in the cell region and in the gate region, and
• the second conductive member is disposed to extend from above the gate trench in the cell region to the gate region through above a part of the cell region in which the protection trench is not provided.