Analysis of GaAs Heterojunction Bipolar Transistor ICs using Passive Detection of Radiative Recombination

Passive detection of the radiative recombination of electrons in the p-type GaAs base of active heterojunction bipolar transistors (HBTs) has been utilised to demonstrate a non-invasive analytical probing technique, compatible with conventional wafer probers, which produces TV pictures of ICs with the active HBTs hiqhlighted. Failure modes, such as in-operative tail current sources and latched stages, were identified in ECL divide by four circuits implemented in 4¿m emitter, 2¿m feature size HBTs, using this technique.