GaInP/GaAs HBTs: state of the art and future trends

The features of GaInP/GaAs HBT technology are illustrated by a description of the advanced general purpose GMMT B20 process, which has f/sub T/ and f/sub max/ typically 50 GHz and a breakdown voltage BV/sub CEO/ in excess of 10 volts. This process has been used for the design of analogue and digital circuits in order to demonstrate a capability for the fabrication of a range of high linearity and broadband circuits for communication systems. A survey of the current state of the art of HBTs is presented, focusing on the process variations needed to address specific applications, and including a comparison with HBT technologies developed on other material combinations. The key parameters determining high-frequency performance are identified in order to assess future trends and performance limitations, including reliability and thermal issues.