Patent ID: 9722040
Date: 2017-08-01
CPC Classifications: H01L

Claim:
1. A method for manufacturing an insulated gate bipolar transistor, which includes a drift layer of a first conductivity type between an emitter side, at which a gate electrode and an emitter electrode are arranged, and a collector side opposite to the emitter side, at which a collector electrode is arranged, wherein the manufacturing method comprises manufacturing steps in the following order: providing a substrate of a second conductivity type, which is opposite to the first conductivity type, the substrate of the second conductivity type having a first side and a second side opposite to the first side, and the substrate of the second conductivity type having a doping concentration of 5*10 creating a first layer of the first conductivity type on the first side by applying a dopant of the first conductivity type by epitaxial growth or deposition, resulting in the first layer having a first layer thickness between 0.5 and 2 μm, creating a drift layer of the first conductivity type on the first layer, which has a low doping concentration, diffusing the dopant such that a buffer layer is created, the buffer layer having a higher doping concentration than the drift layer, wherein in a direction perpendicular to the second side, the buffer layer does not comprise an area of constant doping concentration, creating a base layer of the second conductivity type on the drift layer, creating an emitter layer of the first conductivity type on the base layer, thinning the substrate on the second side such that the remaining part of the substrate forms a collector layer having the collector side to which the collector electrode is formed.