柔性超导电路制备工艺技术研究OA北大核心CSTPCD

The superconducting transition edge sensor(TES)is the key device for the quantum reproduction of the Candela(Cd)unit and single energy X-ray quantum metrology.Transferring the signal from the large-scale TES array to the readout superconducting quantum interference device(SQUID)electronics on the side of the sensor unit relies on the flexible superconducting circuits.Superconducting transmission lines are fabricated on a flexible polyimide substrate for the low thermal conductivity and resistance-free signal transmission.A silicon(Si)wafer is used as a temporary supporting substrate,and a 100 nm Cr film as the sacrificial layer to release the polyimide(PI)film is e-beam evaporated on the Si.Polyimide acid is spin-coated on the Cr film and cured to form the PI film.The Nb/Al thin film transmission lines are fabricated onto the PI film by UV exposure,sputtering and lift-off processes.Then the PI film is released from the silicon substrate due to the high tensile stress of the Cr film,and then the Cr film is wet etched to complete the preparation of flexible superconducting circuits.The superconducting transition temperature Tc of the measured 40 Nb/Al transmission lines are 8.9.～9.02 K,and the residual resistance ratio(rRR,r300 K/r10 K)are 5.83～6.96.At 8 K,the critical current Ic of 38 samples is greater than 1 mA.At 4.2 K,the Ic of all the samples is greater than 1 mA,of which 25 samples are larger than 10 mA.The Tc and Ic satisfy the requirement of the signal transmission of the TES arrays.