Chapter 5 - Insulated gate bipolar transistor

Abstract

The insulated gate bipolar transistor (IGBT) is a successful device because of its superior characteristics. IGBT is a three-terminal power semiconductor switch used to control the electrical energy. Prior to the advent of IGBT, power bipolar junction transistors (BJT) and power metal oxide field effect transistors (MOSFET) were widely used in low to medium power and high-frequency pplications, where the speed of gate turn-off thyristors was not adequate. To improve the power device performance, it is advantageous to have the low on-state resistance of power BJTs with an insulated gate input like that of a power MOSFET. As high stress conditions are quite frequent in circuit applications, it is extremely cost efficient and pertinent to model the IGBT performance under these conditions. However, development of the model can follow only after the physics of device operation under stress conditions imposed by the circuit is properly understood. Physically based process and device simulations are a quick and cheap way of optimizing the IGBT. The emergence of mixed mode circuit simulators in which semiconductor carrier dynamics is optimized withinthe constraints of circuit level switching is a key design tool for this task. The applications of power electronics are varied and various applications have their own specific design requirement. Thereis a wide choice of available power devices. Because of physical, material, and design limitations, none of the presently available devices behave as an ideal switch, which should block arbitrarilylarge forward and reverse voltages with zero current in the off-state, conduct arbitrarily large currents with zero voltage drop in the on-state, and have negligible switching time and power loss.