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

Abstract

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 $\textit {pnp}$ transistor over $\textit {pn}$ superjunction (SJ). This parasitic $\textit {pnp}$ transistor forms Darlington pair with IGBT’s internal $\textit {pnp}$ transistor. The parasitic Darlington pair increases the output current gain and reduces the On-state voltage drop ( ${V}_{\textit {on}}$ ). 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 ( ${E}_{\textit {off}}$ ) and ${V}_{\textit {on}}$ , as compared to the conventional structure.