Full-Gate Verification of Superconducting Integrated Circuit Layouts With InductEx

At present, superconducting integrated circuit layouts are verified through a variety of techniques. A layout-versus-schematic method implemented in Cadence allows extraction of circuit schematics with certain geometry-dependent parameters. Lmeter calculates inductance in a layout network and, with proper setup, may also calculate resistance separately. Recently, InductEx was introduced to calculate multiterminal network inductance in a superconductor structure with support for more complicated 3-D geometries. Here, we present an improvement to InductEx that allows resistance, inductance, and Josephson junction critical current extraction of a full superconducting digital logic gate or cell in a single execution, as well as in reasonable time. We show how InductEx was designed to operate on tape-out ready layouts and, through example, how it is used for full-gate layout verification of contemporary logic cells.