ECE442 Power Semiconductor Devices and Integrated Circuits Insulated Gate Bipolar Transistors (IGBTs) Zheng Yang (ERF 3017, email:
[email protected]) Silicon Power Device Status Overview Silicon Power Rectifiers In the case of low voltage (<100V), the silicon P-i-N rectifier has been replaced by the silicon Schottky rectifier. In the case of high voltage (>100V), the silicon P-i-N rectifier continues to dominate but significant improvements are expected. Silicon Power Switches In the case of low voltage (<100V) systems, the silicon bipolar power transistor has been replaced by the silicon power MOSFET. In the case of high voltage (>100V) systems, the silicon bipolar power transistor has been replaced by the silicon IGBT. Power devices from wide-bandgap materials [cited from “H Amano et al, “The 2018 GaN power electronics roadmap”, Journal of Physics D: Applied Physics 51, 163001 (2018)] Background Pros of power MOSFET: (1) It has an excellent low on-state voltage drop due to the low resistance of the drift region (at low and modest voltages). (2) It is a voltage-controlled device and has a very high input impedance in steady-state due to its MOS gate structure. (3) It has a very fast inherent switching speed in comparison to power BJTs, due to the absence of minority carrier injection. (4) It has superior ruggedness and forward biased safe operating area (SOA) when compared to power BJTs. Cons of power MOSFET: Due to its excellent electrical characteristics, it would be desirable to utilize power MOSFET’s for high voltage power electronics applications. Unfortunately, the specific on-resistance of the drift region increases very rapidly with increasing breakdown voltage because of the need to reduce its doping concentration and increase its thickness.