Igbt device and cell structure thereof, and manufacturing method for cell structure

A manufacturing method for a cell structure of an IGBT, comprising:

• forming a first-type drift region;
• forming a first-type doped pillar region and a second-type doped pillar region on a first surface of the first-type drift region;
• forming a base region, an emitter region and a polysilicon gate on a side of the first-type doped pillar region and the second-type doped pillar region opposite to the first-type drift region;
• forming a heavily doped buffer region and a lightly doped buffer region on a second surface of the first-type drift region opposite to the first surface, wherein a doping concentration of the heavily doped buffer region is greater than a doping concentration of the lightly doped buffer region, and the heavily doped buffer region and the lightly doped buffer region are disposed in a same layer;
• and
• forming a collector region on a side of the heavily doped buffer region and the lightly doped buffer region opposite to the first-type drift region.