Semiconductor device and production method therefor
AssigneeRohm Co., Ltd.
InventorMasaru Takaishi
Life of this patent
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Abstract
A semiconductor device, including: a semiconductor substrate of a first conductivity; and a semiconductor layer provided on the semiconductor substrate and having a super junction structure including drift layers of the first conductivity and RESURF layers of a second conductivity different from the first conductivity, the drift layers and the RESURF layers being laterally arranged in alternate relation parallel to the semiconductor substrate, the RESURF layers being each provided alongside an interior side wall of a trench penetrating through the semiconductor layer, the drift layers each having an isolation region present between the RESURF layer and the semiconductor substrate to prevent the RESURF layer from contacting the semiconductor substrate.
Claims14
A semiconductor device, comprising:
- a semiconductor substrate of a first conductivity;
- and
- a semiconductor layer disposed on the semiconductor substrate, the semiconductor layer including
- a trench penetrating through the semiconductor layer,
- RESURF layers of a second conductivity different from the first conductivity, each RESURF layer being disposed adjacent to an interior side wall of the trench, and
- drift layers of the first conductivity, each having an isolation portion disposed between each of the RESURF layers and the semiconductor substrate to prevent the RESURF layer from contacting the semiconductor substrate,
- wherein the drift layers and the RESURF layers are disposed adjacent to each other in a direction parallel to the semiconductor substrate, each RESURF layer is in contact with at least one of the drift layers, and each of the drift layers is in contact with at least one of the RESURF layers.
A production method for a semiconductor device which includes a semiconductor layer provided on a semiconductor substrate of a first conductivity and including drift layers of the first conductivity and RESURF layers of a second conductivity different from the first conductivity, the drift layers and the RESURF layers being disposed adjacent to each other in a direction parallel to the semiconductor substrate and such that each RESURF layer is in contact with at least one of the drift layers, and each of the drift layers is in contact with at least one of the RESURF layers, the production method comprising the steps of:
- forming a semiconductor layer of the first conductivity on a semiconductor substrate of the first conductivity;
- performing a first trench formation process to form a trench in the semiconductor layer, the trench having a depth such as to reach a middle of the semiconductor layer;
- after the first trench formation step, performing an in-trench impurity introduction process to introduce an impurity of the second conductivity into a portion of the semiconductor layer exposed to an interior side wall of the trench for forming a RESURF layer of the second conductivity alongside the interior side wall of the trench;
- and
- after the in-trench impurity introduction step, performing a second trench formation process to deepen the trench to a depth such as to penetrate through the semiconductor layer to reach the semiconductor substrate.
A production method for a semiconductor device which includes a semiconductor layer provided on a semiconductor substrate of a first conductivity, the semiconductor layer including drift layers of the first conductivity and RESURF layers of a second conductivity different from the first conductivity, the drift layers and the RESURF layers disposed adjacent to each other in a direction parallel to the semiconductor substrate and such that each RESURF layer is in contact with at least one of the drift layers, and each of the drift layers is in contact with at least one of the RESURF layers, the production method comprising the steps of:
- forming a semiconductor layer of the first conductivity on a semiconductor substrate of the first conductivity;
- forming a trench in the semiconductor layer, the trench penetrating through the semiconductor layer to reach the semiconductor substrate;
- and
- performing an in-trench impurity introduction process to implant an impurity of the second conductivity at an inclination angle into a portion of the semiconductor layer exposed to an interior side wall of the trench for forming a RESURF layer of the second conductivity in the portion of the semiconductor layer alongside the interior side wall of the trench, the inclination angle being such that the impurity reaches a limited depthwise range of the interior side wall of the trench shallower than the semiconductor substrate.
Dependencies are inferred from the claim text.