High-speed semiconductor devices for communication systems

The performance of Heterojunction Bipolar Transistors (HBTs) fabricated on novel quaternary InAlGaAs/InGaAs structures grown lattice matched on InP substrates are presented. For the first time the measured pulsed current voltage characteristics on InP HBT devices allow the direct observation of junction thermal effects. The incorporation of quaternary compounds contributes to a significant reduction of the negative resistance effects and an improvement of the output conductance making the devices reported suitable for applications in communication systems operating in microwave range frequencies.