Design and Operation of RSFQ Cell Library Fabricated by Using a 10-${\rm kA/cm}^{2}$ Nb Technology

Abstract

A 10-kA cm 2 Nb AlO Nb junction technology for rapid single flux quantum (RSFQ) integrated circuits has been developed. Modifying our standard 1.6-kA cm 2 cell library, we have implemented elementary cells used to build RSFQ digital-to-analog converters for ac voltage standard applications. The 10-kA cm 2 library cells have been fabricated by utilizing existing process tools. Correct operations of the circuits have been confirmed at low speed. The maximum operating frequencies evaluated by an average-voltage measurement technique were consistent with the scaling rules of RSFQ circuits.Index Terms-Cell library, digital-to-analog converter, high critical current density, rapid single flux quantum, superconductor integrated circuit.

An Integrated Approach towards VLSI Implementation of SFQ Logic using Standard Cell Library and Commercial Tool Suite

“…Standard cell libraries are an important component in designing very large-scale integrated circuits. While early cell libraries [21]- [23] were designed for manual or semi-manual SCE circuit design, modern SCE libraries focus on automated cell placement and interconnect routing tools, adhering to specific routing rules of EDA tools. During the initial years of the SuperTools program, Hypres developed a dual RSFQ/ERSFQ cell library [24][25] for the MIT-LL SFQ5ee 100µm/µm 2 fabrication process [26] that was used to design and experimentally validate circuits targeting high-speed operation [27] [28].…”