We present a superconducting single-flux-quantum (SFQ) mask ROM comprising 2-bit storage cells and a sequential-access driver. Four types of storage cells for 2-bit data (“00,” “10,” “01,” “11”) are adopted for reduction of the cell dimensions, whereas the sequential access is suitable for a single-chip quantum voltage waveform generator implemented with an SFQ-based digital-to-analog converter. 2-bit storage cells of 60 × 70 µm2 are fabricated using a niobium integration technology and tested in liquid helium. Operation of a sequential-access mask ROM with data of 8 bits × 6 words is also demonstrated.
2016 by The Institute of Electronics, Information and Communication Engineers