The IGBT Device

3.4. Transparent Emitter IGBT Structure

The structure for the transparent emitter IGBT was shown on the left-hand side of Fig. 2.5 together with the doping profile on the right-hand side. The DMOS-gate structure for the device is similar to the previous structures and can be replaced by the trench-gate structure as well. The unique aspect of the transparent emitter IGBT structure is its very thin and more lightly doped collector region. The term “transparent” refers to the ability of electrons injected into the collector region to diffuse to the collector contact due to its small thickness. The term “emitter” is used because the collector region of the IGBT actually serves as the emitter of the internal PNP transistor. The smaller dopant charge ...