Test Performance Analysis of Rapid Single Flux Quantum Circuits With Auxiliary Circuits

Fabrication non-uniformity on the wafer causes deviations in the quality of basic devices in superconducting Rapid Single Flux Quantum (RSFQ) circuits, which influences the test performance of RSFQ circuits. Therefore, only small ratio of all chips on one wafer are with high process quality and the Circuit Under Test (CUT) in the chip would work properly during measurement. Currently, the quality of RSFQ chips on the wafer is measured by testing each Process Control Monitor (PCM) chip nearby. PCM chips can obtain the electrical testing results of circuit devices but lack information about the logic and timing of RSFQ circuits. In this paper, we proposed Auxiliary Circuits for Test (ACTs) based on the Linear Feedback Shift Register (LFSR) determine the test performance of CUT from the view of circuit design by the correct operating bias margin of ACT. We successfully fabricated and experimentally verified the high correlations between the ACTs and several CUTs.