Semiconductor device and method of manufacturing semiconductor device
AssigneeMitsubishi Electric Corporation
InventorZe Chen
Life of this patent
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Abstract
Provided are a semiconductor device in which the lifetime of holes is controlled and the switching loss is suppressed, and a method of manufacturing the same. Provided are a semiconductor substrate having a drift layer of a first conductivity type between a first main surface and a second main surface opposite to the first main surface, a first buffer layer of the first conductive type provided between the drift layer and the second main surface in contact with the drift layer, having a resistivity lower than that of the drift layer, and having an impurity concentration higher than that of the drift layer, and a high resistivity layer provided between the first buffer layer and the second main surface and having a resistivity higher than that of the drift layer.
Claims19
A semiconductor device comprising:
- a semiconductor substrate having a drift layer of a first conductivity type between a first main surface and a second main surface opposite to the first main surface;
- a first buffer layer of the first conductive type provided between the drift layer and the second main surface in contact with the drift layer, having a resistivity lower than that of the drift layer, and having an impurity concentration higher than that of the drift layer;
- and
- a high resistivity layer provided between the first buffer layer and the second main surface and having a resistivity higher than that of the drift layer, wherein
- impurities of the first conductivity type of the first buffer layer are protons.
A method of manufacturing a semiconductor device, comprising:
- a step of preparing a semiconductor substrate having a drift layer of a first conductivity type between a first main surface and a second main surface opposite to the first main surface;
- a first implantation step of performing implantation of first conductivity type impurities into the semiconductor substrate in a depth direction from the second main surface toward the first main surface;
- and
- a heat treatment step of forming a first buffer layer having a resistivity lower than that of the drift layer by diffusing the first conductivity type impurities, and forming, between the first buffer layer and the second main surface, a high resistivity layer having a resistivity higher than that of the drift layer without diffusing the first conductivity type impurities.
A semiconductor device comprising:
- a semiconductor substrate having a drift layer of a first conductivity type between a first main surface and a second main surface opposite to the first main surface;
- a first buffer layer of the first conductive type provided between the drift layer and the second main surface in contact with the drift layer, having a resistivity lower than that of the drift layer, and having an impurity concentration higher than that of the drift layer;
- a high resistivity layer provided between the first buffer layer and the second main surface and having a resistivity higher than that of the drift layer;
- and
- an anode layer of a second conductivity type provided in contact with the first main surface side of the drift layer and a cathode layer of the first conductivity type provided on the second main surface side with respect to the high resistivity layer.
Dependencies are inferred from the claim text.