Since the introduction of Insulated Gate Bipolar Transistors (IGBT), they have undergone continuous development, becoming more compact and powerful.
The Carrier Stored Trench-Gate Bipolar Transistor (CSTBT) is such a further development, which has already adopted certain layers of the Trench-IGBT (TIGBT).
Compared to the IGBT, the CSTBT has an additional n-doped layer with a relatively high impurity inserted between the p-layer and the n-layer. This layer acts like a trench and its purpose is to increase the stresses at the layer junctions. It represents a high hurdle for the hole migrations.