Design And Fabrication Of Scalable Superconducting Quantum Devices

Nowadays,quantum computation has a higher profile in the world due to its excellent parallel computation ability.Superconducting quantum computation which based on Josephson junction is regarded as one of the most likely methods to realize quantum computation due to its outstanding scalability and operability.Although a rapid progress has been made in the field recently,there is a great distance between the devices we operate on experiments and the universal quantum computer.One of the main reasons is that millions of physical qubits are required to build enough logical qubits to do some useful computations;nevertheless,there are only tens of physical qubit on the quantum devices we operate.Therefore,developing a mature and scalable qubit device process according to the requirements of the experiment has great significance in the future.This dissertation systematically and deeply analyzes the principles and design methods of superconducting qubit device.The micro-nano fabrication processes including deposition,patterning and packaging are also elaborated in this dissertation.Some encountered problems in processing are listed and the appropriate solutions are given.We also give an overview of our experimental system and a brief introduction to the principle of dilution refrigerator which provide the ultra-low temperature measurement environment for superconducting qubit.The advantages of quantum computation mainly depend on the high-precision simultaneous control and rapid characterization of quantum information processors.We demonstrate a scalable scheme of tunable coupler between two qubits.We are able to control the coupling strength between two qubits by modulating the coupler frequency.The scheme is compatible with our existing device and it promises a higher gate fidelity with current technologies.