Heterostructure bipolar transistors and circuits

The author reviews the progress and basic considerations, and investigates the trends, for the heterostructure bipolar transistor and its digital and analog circuits. The state of the art is reviewed, with attention given to the highest speeds of any semiconductor device and a large level of integration, including the first implementations of compound semiconductor devices in microprocessors. This is followed by a critique of technology trends and future directions, and a summary of scaling considerations of the device. Emphasis is placed on the GaAlAs/GaAs heterostructure system.