Semiconductor device and method for manufacturing semiconductor device

摘要

The present application relates to technology for improving a withstand voltage of a semiconductor device. The semiconductor device includes a termination area that surrounds a cell area. The cell area is provided with a plurality of main trenches. The termination area is provided with one or more termination trenches surrounding the cell area. A termination trench is disposed at an innermost circumference of one or more termination trenches. A body region is disposed on a surface of a drift region. Each main trench reaches the drift region. A gate electrode is provided within each main trench. The termination trench reaches the drift region. Sidewalls and a bottom surface of the termination trench are covered with a insulating layer. A surface of the insulating layer covering the bottom surface of the termination trench is covered with a buried electrode. A gate potential is applied to the buried electrode.

主权项

1. A semiconductor device comprising:
a semiconductor substrate of SiC including a cell area and a termination area that surrounds the cell area; wherein the cell area is provided with a plurality of main trenches, the termination area is provided with a plurality of termination trenches surrounding the cell area, the plurality of termination trenches comprise a first termination trench, which is disposed at an innermost circumference, and one or more second termination trenches, the one or more second termination trenches are disposed on an outer circumference side of the first termination trench, in an inner region of the first termination trench, a first conductive type body region is disposed on a surface of a second conductive type drift region, each of the plurality of main trenches penetrates the body region from a surface of the semiconductor substrate and reaches the drift region, a gate electrode is provided within each of the plurality of main trenches, a bottom surface of each of the plurality of main trenches is covered with a second insulating layer, the first termination trench penetrates the body region from the surface of the semiconductor substrate and reaches the drift region, sidewalls and a bottom surface of the first termination trench are covered with a first insulating layer, the first insulating layer includes at least a covering portion disposed on the bottom surface of the first termination trench, at least a part of a surface of the covering portion is covered with a conductive layer, a thickness of a portion covering the bottom surface of the first insulating layer is thinner than a thickness of the second insulating layer, a depth of the plurality of main trenches is identical to a depth of the first termination trench, each second termination trench surrounds the outer circumference of the first termination trench, is narrower than the first termination trench, penetrates the body region from a surface of the body region, and reaches the drift region, a particular potential is applied to the conductive layer at least during when no on-potential is applied to the gate electrodes, and the particular potential is equal to a potential applied to the gate electrodes or a source electrode when no on-potential is applied to the gate electrodes.