Semiconductor device and manufacturing method thereof
First Claim
1. A semiconductor device comprising:
- a semiconductor substrate of a first conductivity type;
a drift layer of a first conductivity type formed on a first main surface of the semiconductor substrate, a surface of the drift layer having a first area and a second are a which is positioned on an outer periphery of the first area;
a cell portion which is formed in the first area of the drift layer and includes a first base layer of a second conductivity type selectively formed in a surface layer of the first area, a source layer of a first conductivity type selectively formed in a surface layer of the first base layer, a first metallic compound which is formed on the surface layer of the first base layer and a surface layer of the source layer in common, and a control electrode which is formed in the first base layer and the source layer via a first insulating film and has a second metallic compound formed on a top surface thereof;
a terminating portion which is formed in the second area of the drift layer, alleviates an electric field to maintain a breakdown voltage by extending a depletion layer, and includes a second base layer of a second conductivity type selectively formed in a surface layer in the second area of the drift layer, an impurity diffused layer of a second conductivity type formed in a surface layer of the second base layer, and a third metallic compound which is provided to a surface layer of the impurity diffused layer, an end surface thereof on the terminating portion side being positioned on the cell portion side away from an end surface of the impurity diffused layer on the terminating portion side;
a first main electrode formed so as to be in contact with the first metallic compound and the third metallic compound in common; and
a second main electrode formed on a second main surface opposite to the first main surface of the semiconductor substrate.
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Abstract
A semiconductor device includes: a semiconductor substrate of a first conductivity type; a drift layer of a first conductivity type formed on a first main surface of the semiconductor substrate, a surface of the drift layer having a first area and a second area which is positioned on an outer periphery of the first area; a cell portion which is formed in the first area of the drift layer and includes a first base layer of a second conductivity type selectively formed in a surface layer of the first area, a source layer of a first conductivity type selectively formed in a surface layer of the first base layer, a first metallic compound which is formed on the surface layer of the first base layer and a surface layer of the source layer in common, and a control electrode which is formed in the first base layer and the source layer via a first insulating film and has a second metallic compound formed on a top surface thereof; a terminating portion which is formed in the second area of the drift layer, alleviates an electric field to maintain a breakdown voltage by extending a depletion layer, and includes a second base layer of a second conductivity type selectively formed in a surface layer in the second area of the drift layer, an impurity diffused layer of a second conductivity type formed in a surface layer of the second base layer, and a third metallic compound which is provided to a surface layer of the impurity diffused layer, an end surface thereof on the terminating portion side being positioned on the cell portion side away from an end surface of the impurity diffused layer on the terminating portion side; a first main electrode formed so as to be in contact with the first metallic compound and the third metallic compound in common; and a second main electrode formed on a second main surface opposite to the first main surface of the semiconductor substrate.
20 Citations
44 Claims
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1. A semiconductor device comprising:
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a semiconductor substrate of a first conductivity type;
a drift layer of a first conductivity type formed on a first main surface of the semiconductor substrate, a surface of the drift layer having a first area and a second are a which is positioned on an outer periphery of the first area;
a cell portion which is formed in the first area of the drift layer and includes a first base layer of a second conductivity type selectively formed in a surface layer of the first area, a source layer of a first conductivity type selectively formed in a surface layer of the first base layer, a first metallic compound which is formed on the surface layer of the first base layer and a surface layer of the source layer in common, and a control electrode which is formed in the first base layer and the source layer via a first insulating film and has a second metallic compound formed on a top surface thereof;
a terminating portion which is formed in the second area of the drift layer, alleviates an electric field to maintain a breakdown voltage by extending a depletion layer, and includes a second base layer of a second conductivity type selectively formed in a surface layer in the second area of the drift layer, an impurity diffused layer of a second conductivity type formed in a surface layer of the second base layer, and a third metallic compound which is provided to a surface layer of the impurity diffused layer, an end surface thereof on the terminating portion side being positioned on the cell portion side away from an end surface of the impurity diffused layer on the terminating portion side;
a first main electrode formed so as to be in contact with the first metallic compound and the third metallic compound in common; and
a second main electrode formed on a second main surface opposite to the first main surface of the semiconductor substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A semiconductor device comprising:
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a semiconductor substrate of a first conductivity type;
a drift layer of a first conductivity type formed on a first main surface of the semiconductor substrate and has a first area and a second area which is positioned on an outer periphery of the first area;
a cell portion which is formed in the first area of the drift layer, and includes a first base layer of a second conductivity type selectively formed in a surface layer of the first area, a trench formed so as to extend from a surface of the first base layer to the inside of the drift layer, a first insulating film formed on a bottom surface and side surfaces of the trench, a source layer of a first conductivity type selectively formed in a surface layer of the first base layer so as to be in contact with the first insulating film, a first metallic compound formed on a surface of the first base layer and a surface of the source layer in common, and a control electrode which is formed so as to fill the trench via the first insulating film and has a second metallic compound formed on a top face thereof;
a terminating portion which is formed in the second area of the drift layer and alleviates an electric field to maintain a breakdown voltage by extending a depletion layer, and includes a second base layer of a second conductivity type selectively formed in a surface layer in the second area of the drift layer, an impurity diffused layer of a second conductivity type formed in a surface layer of the second base layer, and a third metallic compound which is formed in a surface layer in the impurity diffused layer, an end surface thereof on the terminating portion side being positioned on the cell portion side away from an end surface of the impurity diffused layer on the terminating portion side;
a first main electrode formed so as to be in contact with the first metallic compound and the third metallic compound in common; and
a second main electrode formed on a second main surface opposite to the first main surface of the semiconductor substrate. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A manufacturing method of a semiconductor device comprising:
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forming a drift layer of a first conductivity on a first main surface of a semiconductor substrate of a first conductivity type, a surface of the drift layer having a first area for a cell portion and a second area for a terminating portion which is positioned on an outer periphery of the first area and alleviates an electric field to maintain a breakdown voltage by extending a depletion layer;
forming a first insulating film with a first thickness in the second area on the drift layer;
forming a second insulating film having a second thickness smaller than the first thickness in the first area on the drift layer;
forming a control electrode by depositing an electrode material on the second insulting film and patterning it;
forming a first base layer in the first area and a second base layer in the second area by implanting a second conductivity impurity into the drift layer using the control electrode and the first insulating film as a mask and then by a heat treatment to diffuse it;
selectively forming an impurity diffusion layer in a surface layer of the second base layer by implanting a second conductivity impurity into the second base layer by using a resist formed on the control electrode and the first insulating film as a mask and then by a heat treatment to diffuse it;
selectively forming a source layer of a first conductivity type in a surface layer of the first base layer; and
forming a first metallic compound and a second metallic compound in surface layers of the source layer and of the control electrode, respectively, by depositing a metallic material on the source layer, the control electrode and the impurity diffused layer, causing the source layer, the control electrode, the impurity diffused layer to react with the metallic material by a heat treatment, and then selectively removing the metallic material, and forming a third metallic compound in a surface layer of the impurity diffused layer so that an end surface thereof on the terminating portion side is positioned on the cell portion side away from an end portion of the impurity diffused layer on the terminating portion side. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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34. A manufacturing method of a semiconductor device comprising:
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forming a drift layer of a first conductivity type on a first main surface of a semiconductor substrate of a first conductivity type, a surface of the drift layer having a first area for a cell portion and a second area for a terminating portion which is positioned on an outer periphery of the first area and alleviates an electric field to maintain a breakdown voltage by extending a depletion layer;
forming a first insulating film with a first thickness in the second area on the drift layer;
forming a base layer by implanting a second conductivity type impurity into the drift layer and then diffusing it by a heat treatment;
selectively forming an impurity diffused layer in a surface layer of the base layer in the second area by implanting a second conductivity type impurity into the base layer by using a resist and then diffusing it by a heat treatment;
selectively forming a source layer of a first conductivity type in a surface layer of the base layer in the first area;
forming a trench which reaches the drift layer from a surface of the source layer through the base layer and forming a second insulating film on a bottom surface and side surfaces of the trench;
forming a control electrode by filling the trench via the second insulating film with an electrode material; and
forming a first metallic compound and a second metallic compound to surface layers of the source layer and of the control electrode, respectively, by depositing a metallic material on the source layer, the control electrode and the impurity diffused layer, causing the source layer, the control electrode and the impurity diffused layer to react with the metallic material by a heat treatment and then selectively removing the metallic material, and forming a third metallic compound to a surface layer of the impurity diffused layer in such a manner that an end surface thereof on the terminating portion side is positioned on the cell portion side away from an end surface of the impurity diffused layer on the terminating portion side. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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Specification