Prospects of High-Speed Semiconductor Devices

Abstract

Concepts, technologies, and performance of high speed devices are reviewed. Among the devices treated are the modulation doped GaAs/AlGaAs heterojunction transistors (MODFET), heterojunction bipolar transistors (HBT), resonant tunneling devices (RTD) and hot electron transistors (HET) with semiconductor or metal type base. A contrast is drawn between the intrinsic switching speed and the extrinsic speed which is dominated by, but often overlooked, parasitic resistances and capacitances. It is shown that because of parasitics, not just the carrier velocity but the device current needs optimization.