The insulated-gate bipolar transistors (IGBTs) have been widely used in a variety of power switching applications such as industrial motor drives, automotive and traction controls, renewables, white goods, and so forth. Currently, most of the IGBT applications utilize hard-switching configurations. A general requirement for IGBTs used in hard-switching applications is to achieve good overall device performance in terms of low conduction and switching losses, fast switching speed, high reliability, and low switching noise. In this thesis, advanced IGBT structures are proposed and demonstrated to improve the overall device performance of IGBTs for high-speed, hard-switching applications.

First, a new 1200 V-class fin p-body IGBT (Fin-P IGBT) is designed and experimentally dem...[ Read more ]

The insulated-gate bipolar transistors (IGBTs) have been widely used in a variety of power switching applications such as industrial motor drives, automotive and traction controls, renewables, white goods, and so forth. Currently, most of the IGBT applications utilize hard-switching configurations. A general requirement for IGBTs used in hard-switching applications is to achieve good overall device performance in terms of low conduction and switching losses, fast switching speed, high reliability, and low switching noise. In this thesis, advanced IGBT structures are proposed and demonstrated to improve the overall device performance of IGBTs for high-speed, hard-switching applications.

First, a new 1200 V-class fin p-body IGBT (Fin-P IGBT) is designed and experimentally demonstrated. The device features wide trenches and spacer gates, which is implemented by using a simple contact-first process. Compared with the conventional IGBTs with floating-p regions, the Fin-P IGBT offers significantly lower Miller capacitance (− 60% at V_CE of 15 V), gate charge (− 46%), dV/dt noise (lower limit – 82%), and turn-on energy loss (− 53% at a typical dV/dt of 10 kV/μs), while still maintaining a similar on-state voltage drop (V_on). Second, a new ultra-narrow-mesas fin p-body (U-Fin-P) IGBT is proposed to further reduce V_on of the Fin-P IGBT. The U-Fin-P IGBT features a much narrower mesa width compared with the Fin-P IGBT; whereas the difficulty of doing emitter contact lithography on top of the ultra-narrow mesa regions is resolved by using a self-aligned contact formation process design. Simulation results show that for the same turn-off energy loss, V_on (at 150 °C) of the U-Fin-P IGBT is ~ 21 % lower than that of the Fin-P IGBT. Third, a new 1200 V-class reverse-conducting IGBT (RC-IGBT) with deep metal plugs at the emitter-side is proposed. Simulation results show that the proposed device can achieve a significant reduction in the diode-mode reverse-recovery loss, E_rr, (− 70% at R.T. and − 57% at 150°C) without degrading the IGBT-mode performance compared with conventional RC-IGBT. Furthermore, the proposed RC-IGBT can also achieve comparable diode-mode performance in terms of E_rr and V_f (diode-mode forward voltage) compared with those of the state-of-the-art discrete free-wheeling diodes for hard-switching applications.