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We have developed a new fabrication method for a high-Tcsuperconducting quantum interference device (SQUID) with an integrated multiturn input coil to improve the fabrication yield. The method consists of a new multi-SQUID layout and an additional patterning process. In this layout, each input coil is shunted by a shunt inductor to avoid an increase in the inductance of the flux transformer. After preliminary evaluation, the shunt inductor connected to the preferred SQUID is cut to activate the input coil. We demonstrated a drastic improvement in fabrication yield to obtain white field noise less than 25 fT/Hz1/2from 25 to 83%.

We have developed a new fabrication method for a high-Tc superconducting quantum interference device (SQUID) with an integrated multiturn input coil to improve the fabrication yield. The method consists of a new multi-SQUID layout and an additional patterning process. In this layout, each input coil is shunted by a shunt inductor to avoid an increase in the inductance of the flux transformer. After preliminary evaluation, the shunt inductor connected to the preferred SQUID is cut to activate the input coil. We demonstrated a drastic improvement in fabrication yield to obtain white field noise less than 25 fT/Hz1/2 from 25 to 83%.

Superconductor-semiconductor-superconductor weak links with a normal layer of InSb thin film were fabricated. A large normal resistance of 16 ? and a critical supercurrent of 50 µA were obtained at 4.2 K for a channel length of 0.19 µm between Nb electrodes. The normal resistance of 16 ? is about 40 times as large as that of a junction with the normal layer of a Si bulk crystal.

A Nb-InSb-Nb planar junction with a normal layer of InSb thin film was fabricated by a new process. In this report, the details of the fabrication process and properties of the junction are discussed. The Nb-InSb-Nb junction fabricated using the new process showed a supercurrent. This means that there is no notable barrier, such as the Schottky barrier at the interface between Nb and InSb. The InSb film has a mobility of 500?700 cm2/V·s, which is 17?23 times larger than that of Si. This makes it possible to realize the superconductor-semiconductor-superconductor junction with a low carrier density of 1017cm-3.

We studied In2O3for use as an intermediate layer between the YBCO emitter electrode and the SrTiO3base region of dielectric-base transistors (DBT). We fabricated and tested a YBCO(001)/In2O3(100)/SrTiO3(110) hetero-structure by using a laser-ablation deposition technique with high-density targets. Our YBCO/In2O3/n-SrTiO3diode structure showed a current density that was one order of magnitude larger than with an MgO intermediate layer.

We fabricated a ramp-edge Josephson junction with a 17-nm-thick indium-tin-oxide (ITO) (1 wt%) barrier. ITO is considered to be a useful barrier material for Josephson junctions because it has a low permittivity of 20, a mobility of 100 cm2/V·s, a carrier density of 1.1×1020cm-3, and (100) orientation on YBa2Cu3O7-x(YBCO) (001). We examined 8 junctions with widths ranging from 6 µm to 10 µm at temperatures varying from 20 K to 80 K. All of the junctions showed resistively shunted junction (RSJ)-type I-Vcharacteristics at temperatures between 20 K and 77 K. The maximum critical current density, Jc, and critical current normal resistance products, IcRn, were 4.0×104A/cm2and 2.2 mV, and the averages of these values at 20 K were 2.7×104A/cm2and 1.7 mV, respectively. The standard deviation of Icand IcRnwere ?I=33% and ?IcRn=21%, respectively. Icwas suppressed well by a magnetic field.