Extracting the HBT series parasitics under active bias conditions

A method for directly determining the series access impedances of heterojunction bipolar transistors (HBT) is presented. Unlike previous methods which use either specific bias conditions (open-collector regime) at high base current densities or special test-structures, this method determines the impedances under normal active bias conditions. Reliable extraction of the contact base resistance and inductance, collector and emitter inductances is possible. A new test to verify measured data or model validity using passive circuit techniques is also described