利用隧道桥屏蔽结构抑制超导量子电路中的串扰OA北大核心CSTPCD

Superconducting quantum circuit is one of the leading approaches for realizing universal quantum computation.As the chip integration continues to increase,circuit design faces the challenges of complex wiring and signal crosstalk.In order to suppress the signal crosstalk on the chip,a novel on-chip structure covering coplanar waveguides,called tunnel bridge,is proposed based on the electromagnetic shielding principle of the coaxial line.In this paper,we simulate the chip circuit,with the tunnel bridge added,by using the finite element method,and the optimal impedance matching design parameters are obtained.The simulation results of the chip signal crosstalk show that,compared with conventional coplanar waveguides,the addition of the tunnel bridge brings three orders of magnitude shielding effect on the vertical electric field between top and bottom chips in flip-chip design.For planar single chip,the crosstalk between microwave drive lines are reduced by approximately 16 dB,and the crosstalk current caused by the DC flux bias lines are reduced by around 70％,yielding a 40％improvement over traditional air bridge schemes.The micro-fabrication process of tunnel bridge is also studied in this paper,and a stable sample fabrication process is achieved.The tunnel bridge structure has remarkable crosstalk suppression effect,thus a great prospect of application in large-scale superconducting qubit chips.