Location of defective cells in HBT power amplifier arrays using IR emission microscopy

Abstract

A logical method and approach to a very low percentage failure rate problem for HBT PA products is presented. The value of the IR emission technique coupled with junction breakdown measurements demonstrated the capability to identify a potentially bad HBT cell contained in an array of a few hundred HBT cells. HBT cells with low junction breakdown characteristics are demonstrated to be a potential killer to the whole PA. The cause of low breakdown can be either process or epi-layer defects, as well as by ESD or reverse voltage under certain conditions.