NEW HIGH-SPEED III-V DEVICES FOR INTEGRATED CIRCUITS.

This paper traces the research and development steps that led to selectively doped heterostructure transistors and integrated circuits. The transistor is the fastest switching transistor known, whereas integrated circuits built with the device outperform all other circuits of equivalent function. Doping experiments resulted in the concept of doping the wider bandgap (Al, Ga)As to supply carriers to the undoped narrower bandgap GaAs. The removal of impurities from the GaAs layer results in higher carrier mobility due to greatly reduced impurity scattering. This technique, called modulation doping, resulted in a new generation of higher speed devices and circuits. The basic device is known as a selectively doped heterostructure transistor or SDHT.