Silicon Technology Inspired Test Structures and Methodology for SFQ Model-to-Hardware Correlation

A test structure suite to measure circuit delays, power, and operating margins of single flux quantum (SFQ) circuits and to derive key parameters directly from dc testable high-speed circuits is described. This suite comprises a set of ring oscillators and a time-differential experiment as well as isolated circuit components. Measured data are compared to the results obtained from circuit simulations conducted in a design environment used for more complex chip designs. This approach, which enables tracking of process technology and validation of device and circuit models in a self-consistent manner, is inspired by a similar methodology for silicon technology deployed successfully by IBM and its alliance partners.