Bipolar punch-through semiconductor device and method for manufacturing such a semiconductor device

摘要

A method for manufacturing a bipolar punch-through semiconductor device is disclosed, which includes providing a wafer having a first and a second side, wherein on the first side a high-doped layer of the first conductivity type having constant high doping concentration is arranged; epitaxially growing a low-doped layer of the first conductivity type on the first side; performing a diffusion step by which a diffused inter-space region is created at the inter-space of the layers; creating at least one layer of the second conductivity type on the first side; and reducing the wafer thickness within the high-doped layer on the second side so that a buffer layer is created, which can include the inter-space region and the remaining part of the high-doped layer, wherein the doping profile of the buffer layer decreases steadily from the doping concentration of the high-doped region to the doping concentration of the drift layer.

主权项

1. A method for manufacturing a bipolar punch-through semiconductor device having at least a two-layer structure with layers of a first and a second conductivity type, which second conductivity type is different from the first conductivity type, the method comprising:
providing a wafer which comprises a first side and a second side, a wafer thickness and a high-doped layer of the first conductivity type at the first side, wherein the high-doped layer has a constant high doping concentration; forming a low-doped layer of the first conductivity type on top of the high-doped layer by epitaxial growth on the first side; performing a diffusion step, to form a diffused inter-space region, which comprises a portion of the high-doped layer and a portion of the low-doped layer, wherein the portions are arranged adjacent to each other, wherein the diffused inter-space region has a doping concentration higher than the doping concentration of the low-doped layer and lower than the doping concentration of the high-doped layer, wherein the remaining part of the low-doped layer forms a drift layer; forming at least one layer of the second conductivity type on top of the drift layer on the first side; and reducing the wafer thickness on the second side within the high-doped layer to form a buffer layer comprising both the inter-space region and the remaining portion of the high-doped layer, wherein the remaining portion of the high-doped layer forms a high-doped region, wherein the doping profile of the buffer layer decreases steadily from the doping concentration of the high-doped region to the doping concentration of the drift layer.