US 8,803,192 B2Granted

Bipolar non-punch-through power semiconductor device

AssigneeABB Technology AG

InventorsJan Vobecky, Munaf Rahimo

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Abstract

An exemplary bipolar non-punch-through power semiconductor device includes a semiconductor wafer and a first electrical contact on a first main side and a second electrical contact on a second main side. The wafer has an inner region with a wafer thickness and a termination region that surrounds the inner region, such that the wafer thickness is reduced at least on the first main side with a negative bevel. The semiconductor wafer has at least a two-layer structure with layers of different conductivity types, which can include a drift layer of a first conductivity type, a first layer of a second conductivity type at a first layer depth and directly connected to the drift layer on the first main side and contacting the first electrical contact, and a second layer of the second conductivity type arranged in the termination region on the first main side up to a second layer depth.

Claims25

Dependent claims

A bipolar non-punch-through power semiconductor device comprising:

a semiconductor wafer and a first electrical contact formed on a first main side of the wafer and a second electrical contact formed on a second main side of the wafer opposite the first main side;
wherein said semiconductor wafer includes at least a two-layer structure with layers of different conductivity types,
said at least two-layer structure having:
a drift layer of a first conductivity type,
a first layer of a second conductivity type directly connected to the drift layer towards the first main side and contacting the first electrical contact, and
wherein said semiconductor wafer includes an inner region having a constant wafer thickness measured between the first and second main side and a termination region, which surrounds the inner region and in which the wafer thickness is reduced at least on the first main side by a negative bevel,
wherein the first layer extends to a first layer depth, the first layer depth being measured from a plane, in which the first main side is arranged within the inner region and wherein the first layer laterally extends into the termination region, and
wherein the drift layer extends to a drift layer depth, the drift layer depth being measured within the inner region from the plane, in which the first main side is arranged within the inner region,
a second layer of the second conductivity type is arranged in the termination region on the first main side, the second layer extending to the edge of the device, the second layer being arranged up to a second layer depth, the second layer depth being measured from a plane, in which the first main side is arranged within the inner region, and in that the second layer depth is larger than the first layer depth and shallower than the drift layer depth, a maximum doping concentration of the second layer is lower than a maximum doping concentration of the first layer, and
wherein the first layer depth is at most 45 μm.

7 more elements

A method for manufacturing a bipolar non-punch-through power semiconductor device, which comprises a first electrical contact on a first main side and a second electrical contact on a second main side opposite the first main side and at least a two-layer structure with layers of different conductivity types, the method comprising:

providing a wafer of a first conductivity type;
creating a weakly doped second layer on the first main side by applying a first mask on the first main side, the first mask covering an inner region of the wafer;
applying ions on the first main side in a termination region UP to the edge of the wafer, which surrounds the inner region, and diffusing the ions in the termination region into the wafer up to a second layer depth;
removing the first mask;
creating a first layer, which is higher doped than the second layer, by applying ions on the first main side and diffusing the ions into the wafer into a first layer depth of at most 45 μm from the first main side, which first layer depth is lower than the second layer depth;
and
applying the first and second electrical contacts on the wafer on the inner region, then creating a negative bevel of the wafer on the first main side in the termination region by partly removing wafer material from the first main side in the termination region.

4 more elements

Dependencies are inferred from the claim text.