Chapter 2 - Power Semiconductor Devices

Abstract

This chapter describes important types of modem power semiconductors, including thyristors, triacs, diodes, and static induction transistor (SIT), Integrated Gate-Commutated Thyristors (IGCTs) and Gate Turn-off thyristors (GTOs), Bipolar Power Transistor (BPT or BJT) and power MOSFETs and Insulated Gate Bipolar Transistor (IGBTs), as well as their electrical characteristics. The invention of the IGBT in 1983 and its commercial introduction in 1985 have been important milestones in the history of power devices. The chapter summarizes the power capabilities of modem devices and their future trends. Most of the power devices are available in modular form. There is no exaggeration in saying that the power electronics evolution of modern-day world has been possible primarily due to device evolution. Power semiconductor evolution has closely followed the evolution of microelectronics. Thyristors or silicon-controlled rectifiers and triacs are essentially the forerunners of modem power-semiconductor devices, which operate mainly on a utility system and contribute to power quality and lagging power factor problems. IGCTs and GTOs are high-power gate-controlled devices that are used in multi-megawatt applications. The BJT, once a very important device, has become obsolete. Power MOSFETs and IGBTs are self-controlled insulated- gate devices that are extremely important in the context of modern world. An SIT is the solid-state equivalent of the vacuum triode; it has a high-conduction drop.