High-Speed III-V Semiconductor Devices

Abstract

In this chapter we present a new class of high-speed III-V compound semiconductor devices, and discuss the basic device physics, operation principles, and general characteristics of these devices. The devices to be discussed here include the GaAs-based metal-semiconductor field-effect transistors (MESFETs), modulation doped field-effect transistors (MODFETs), heterojunction bipolar transistors (HBTs), hot-electron transistors (HETs), resonant tunneling devices (RTDs), and Gunn effect devices. In addition to GaAs based devices, the InP-based MODFETs and HBTs will also be discussed. The GaAs-based high-speed devices are usually fabricated by using the GaAs/AlGaAs material system grown on a semiinsulating GaAs substrate, while the InP-based devices use the InAlAs/InGaAs or InGaAs/InP material grown on a semiinsulating InP substrate. Although the GaAs/AlGaAs material technology is more mature than that of the InP/InGaAs material system, the InP-based devices can be operated at a higher frequency and speed than that of the GaAs-based devices. This is due to the fact that the InGaAs/InP material system has a higher electron mobility and smaller electron effective mass than that of the AlGaAs/GaAs material system.