Automated extraction of matching parameters for bipolar transistor technologies

We present here a technique for automatically producing statistical data for bias and resistor mis-match on bipolar transistor technologies by use of a nulled differential amplifier. The method has been developed to enable automatic wafer probe and the generation of distributions and wafer maps. The data is analysed using software from the SAS Institute and the method allows extraction of both resistor and V/sub BE/ mis-match from a single circuit.