High-Yield Fabrication Method for High-$T_{\text{c}}$ Superconducting Quantum Interference Device Magnetometer with Integrated Multiturn Input Coil

Abstract

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%.

Fabrication of HTS ramp-edge-type Josephson junctions and SQUIDs using various YBCO-derivatives as barrier materials

“…We devised the layout design in which one inductor exhibiting moderate properties could be chosen to obtain available magnetometers or gradiometers. 41) Collecting chips exhibiting 2I c > 15 μA and ΔV > 15 μV for system applications, the yield was approximately one half. When LBC was used as the barrier material, the yield was relatively good.…”

A high sensitivity magnetometer via the combination of ultrahigh-Q fiber cavity and frequency-locking technology

“…3) As a comprehensive subject of optics, electromagnetism, quantum mechanics and other disciplines, weak magnetic detection has attracted extensive attention. In the past two decades, the magnetic field measurement system dominated by superconducting quantum interferometer device, 4,5) atomic magnetometer, 6,7) NV color center magnetometer 8) and external high quality factor resonator 9) technology has gradually matured.…”