Terminal structure of power device and manufacturing method thereof, and power device
A terminal structure of a power device includes a substrate and a plurality of field limiting rings disposed on a first surface of the substrate. The substrate includes a drift layer and a doped layer. The doped layer is formed through diffusion inward from the first surface of the substrate. The doped layer and the drift layer are a first conductivity type, and an impurity concentration of the doped layer is greater than an impurity concentration of the drift layer. The field limiting rings are a second conductivity type. In the terminal structure, lateral diffusion of impurities in the field limiting rings is limited through a design of the doped layer.
1 . A terminal structure of a power device, wherein the terminal structure comprises:
a substrate comprising a drift layer and a doped layer, wherein the doped layer is diffused inward from a first surface of the substrate and is disposed within a part of the drift layer that is adjacent to the first surface, wherein the doped layer and the drift layer are of a first conductivity type, and wherein a first impurity concentration of the doped layer is greater than a second impurity concentration of the drift layer;
a plurality of field limiting rings disposed on the first surface, wherein the plurality of field limiting rings is a second conductivity type; and
a cutoff ring of the first conductivity type,
wherein the cutoff ring is located at an outer edge of the substrate.
2 . The terminal structure of claim 1 , wherein the first impurity concentration is less than a third impurity concentration of the field limiting rings.
3 . The terminal structure of claim 2 , wherein the first impurity concentration is 10 13 cubic centimeters (cm 3 ) to 10 15 cm 3 .
4 . The terminal structure of claim 1 , wherein a first junction depth of the doped layer is less than a second junction depth of the plurality of field limiting rings.
5 . The terminal structure of claim 4 , wherein a first range of the first junction depth is 3 micrometers (μm) to 5 μm, and wherein a second range of the second junction depth is 5 μm to 15 μm.
6 . The terminal structure of claim 1 , further comprising a field oxide layer disposed on the first surface and connected to the plurality of field limiting rings.
7 . The terminal structure of claim 6 , further comprising a field plate disposed on a side of the field oxide layer that is away from the first surface.
8 . The terminal structure of claim 1 , wherein the first conductivity type is an N type, and the second conductivity type is a P type; or wherein the first conductivity type is a P type, and the second conductivity type is an N type.
9 . A power device comprising:
at least one of a collector layer or a buffer layer;
a terminal structure comprising:
a substrate comprising a drift layer and a doped layer, wherein the doped layer is diffused inward from a first surface of the substrate and is disposed within a part of the drift layer that is adjacent to the first surface, wherein the doped layer and the drift layer are of a first conductivity type, wherein a first impurity concentration of the doped layer is greater than a second impurity concentration of the drift layer, wherein the at least one of the collector layer or the buffer layer is disposed on a second surface of the substrate opposite to the first surface;
a plurality of field limiting rings disposed on the first surface, wherein the plurality of field limiting rings is a second conductivity type; and
a cutoff ring of the first conductivity type,
wherein the cutoff ring is located at an outer edge of the substrate.
10 . The power device of claim 9 , wherein the first impurity concentration is less than a third impurity concentration of the field limiting rings.
11 . The power device of claim 9 , wherein the first impurity concentration is 10 13 cubic centimeters (cm 3 ) to 10 15 cm 3 .
12 . The power device of claim 9 , wherein a first junction depth of the doped layer is less than a second junction depth of the plurality of field limiting rings.
13 . The power device of claim 12 , wherein a first range of the first junction depth is 3 micrometers (μm) to 5 μm, and wherein a second range of the second junction depth is 5 μm to 15 μm.
14 . A terminal structure of a power device, wherein the terminal structure comprises:
a substrate comprising a drift layer and a doped layer, wherein the doped layer is diffused inward from a first surface of the substrate, is disposed within a part of the drift layer that is adjacent to the first surface, and extends laterally within the drift layer from an inner region of the terminal structure toward an outer edge of the substrate, wherein the doped layer and the drift layer are of a first conductivity type, and wherein a first impurity concentration of the doped layer is greater than a second impurity concentration of the drift layer;
a plurality of field limiting rings disposed on the first surface, wherein the plurality of field limiting rings is a second conductivity type; and
a cutoff ring of the first conductivity type,
wherein the cutoff ring is located at the outer edge.
15 . The terminal structure of claim 14 , wherein the first impurity concentration is less than a third impurity concentration of the field limiting rings.
16 . The terminal structure of claim 15 , wherein the first impurity concentration is 10 13 cubic centimeters (cm 3 ) to 10 15 cm 3 .
17 . The terminal structure of claim 14 , wherein a first junction depth of the doped layer is less than a second junction depth of the plurality of field limiting rings.
18 . The terminal structure of claim 17 , wherein a first range of the first junction depth is 3 micrometers (μm) to 5 μm, and wherein a second range of the second junction depth is 5 μm to 15 μm.
19 . The terminal structure of claim 14 , further comprising a field oxide layer disposed on the first surface and connected to the plurality of field limiting rings.
20 . The terminal structure of claim 19 , further comprising a field plate disposed on a side of the field oxide layer that is away from the first surface.