Hybrid superconducting junctions

Cecilia Holmqvist

Uttam Ghoshal, T. Van Duzer, Harry Kroger

The authors describe the development of circuit models, applications of superconducting field effect transistors (SFETs), and higher-voltage Josephson junction (HVJJ) circuits which are important for the feasibility of several novel hybrid superconducting-semiconducting circuits. They also discuss the delay optimization involved in designing and embedding interface circuits in a hybrid superconductor-semiconductor technology. It is noted that, with the advances made in semiconductor technologies, interfaces between the two technologies are practical now and the advantages of hybrid circuits in various applications should be realizable in practice. In the case of interfacing typical Nb-based Josephson junction circuits to 0.5 mu m CMOS technologies, it was estimated that the minimum delay through the interface is approximately 110 ps and the optimum number of junctions in each branch of the HVJJ circuits is 10.>

Roland Grein

Angela Kou, Marta Pita‐Vidal, Arno Bargerbos +7 more

Akira Shoji

In this paper, the author describes studies on electronic devices and circuits utilizing both of superconductors and semniconductors. First, a design of an interface circuit composed of Josephson junctions and MOSFETs is described. The Josephson-MOS interface circuit will be used for realizing high-speed data communication between a Josephson digital circuit and a semiconductor one. Second, fabrication and characterization of MOSFETs with superconductive NbN gate electrodes are described. The use of superconductive gates makes it easy to hybridize MOSFETs with Josephson junctions. Finally, studies of Josephson-CMOS hybrid memory circuits are introduced.

Kaveh Delfanazari, Reuben K. Puddy, Ma, P +8 more

In this paper, we experimentally demonstrate a hybrid superconducting-semiconducting (S-Sm) circuit consisting of eight planar and ballistic Nb-In0.75Ga0.25As-Nb Josephson junctions. E-beam lithography was used to fabricate the Josephson junctions on an InGaAs chip. In contrast to our previous studies on long junctions that were fabricated by photolithography, in this study, we observe the induced superconductivity in an In0.75Ga0.25As quantum well at higher temperatures, between T= 0.3 and 1.4 K (3He cryostat temperature range). The induced superconducting gap of & #x0394;ind= 0.65 meV was measured at lowest base temperature T= 300 mK. The effect of temperature and magnetic fields B on the induced superconductivity are presented. Our results suggest that our In0.75Ga0.25As heterojunctions is a promising scalable material system for quantum processing and computing applications.