INSULATED GATE BIPOLAR TRANSISTOR AND METHOD FOR MANUFACTURING SUCH AN INSULATED GATE BIPOLAR TRANSISTOR

An insulated gate bipolar is produced, wherein the following steps are performed: (a) providing a lowly n doped substrate (1) having an emitter side (20) and a collector side (27), (b) forming n and p doped layers on the emitter side (20), (c) thinning the substrate (1) on the collector side (27), (d) implanting an n first dopant (82) on the collector side (27) into a depth of at most 2 µm, (e) forming a first buffer layer (8) by annealing the first dopant (82), (f) applying a surface layer comprising an n second dopant on top of the collector side (27), (g) forming a second buffer layer (9) by annealing the second dopant, wherein the second buffer layer (9) having a lower maximum doping concentration than the first buffer layer (8), (h) applying a p third dopant at the collector side (27), (i) forming a collector layer (6) by annealing the third dopant.