Lateral Variation-Doped Insulated Gate Bipolar Transistor for Low On-State Voltage With Low Loss

In this letter, a new structure of Insulated Gate Bipolar Transistor (IGBT) with lateral variation doping concept in epitaxial region is presented. In the drift region, the lateral variation doping profile acts as a parasitic wide base pnp transistor over pn superjunction (SJ). This parasitic pnp transistor forms Darlington pair with IGBT's internal pnp transistor. The parasitic Darlington pair increases the output current gain and reduces the On-state voltage drop (V-on). Apart from this, p(-)-col in the collector layer provides increment in recombination rate of minority charges. An increase in the recombination rate reduces the minority carrier life-time, which further reduces the turn-off and delay time. Improvement in the turn-off time leads to optimize the trade-off between turn-off energy loss (E-off) and V-on, as compared to the conventional structure.