Large-signal reliability of silicon-germanium heterojunction bipolar transistor amplifiers

Abstract

This work focuses on the electrothermal impact of large voltage swings on silicon-germanium heterojunction bipolar transistors used in radio frequency amplifiers. Measurement data and simulation results are used to present a clear understanding of reliable operation for these devices, and techniques are introduced to give circuit designers the tools necessary to optimize the performance-reliability trade-off in power amplifier and low-noise amplifier designs. Clear reliability guidelines are discussed. An approach for evaluating mutual heating in power amplifiers is presented, whereby base currents are monitored individually, providing insight into the thermal considerations important for the implementation of resized power cores. Since resizing would also require tunable matching networks to be effective, arrays of switched capacitors are also evaluated on high-resistivity substrate.