Manufacturing method of semiconductor device
First Claim
1. A manufacturing method of a semiconductor device comprising:
- 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, the impurity diffused layer having first and second opposing end surfaces, the first end surface being located closer to the first area than the second end surface;
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, the third metallic compound having third and fourth opposing end surfaces, the third end surface being located closer to the first area than the fourth end surface, and the fourth end surface being spaced from the second end surface on an upper surface of the impurity diffused region by a distance.
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Abstract
A semiconductor device including a drift layer of a first conductivity type formed on a surface of a semiconductor substrate. A surface of the drift layer has a second area positioned on an outer periphery of a first area. A cell portion formed in the first area includes a first base layer of a second conductivity type, a source layer and a control electrode formed in the first base layer and the source layer. The device also includes a terminating portion formed in the drift layer including a second base layer of a second conductivity type, an impurity diffused layer of a second conductivity type, and a metallic compound whose end surface on the terminating portion side is positioned on the cell portion side away from the end surface of the impurity diffused layer on the terminating portion side.
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Citations
11 Claims
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1. 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, the impurity diffused layer having first and second opposing end surfaces, the first end surface being located closer to the first area than the second end surface; 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, the third metallic compound having third and fourth opposing end surfaces, the third end surface being located closer to the first area than the fourth end surface, and the fourth end surface being spaced from the second end surface on an upper surface of the impurity diffused region by a distance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification