Identification of Humidity Related Failure Mechanisms in GaAs Based HBT's
 
Peter Dai, Philip Canfield, Gavin Kelley and Joanne Zhou
Reliability and Failure Analysis, GaAs Manufacturing Operations, Conexant Systems, Inc.
 
Humidity related failure mechanisms in GaAs based HBT power amplifiers have been investigated. Both electrical and photoemission techniques are used to characterize and identify the degradation of the base-collector junction. Moisture penetration to the HBT surface reduces the junction breakdown voltage and can lead to catastrophic short failure. Observation of biased side emission from cross-sectioned HBT's demonstrated that the breakdown can be surface related.