Fabrication and room temperature characterization of trilayer junctions for the development of superconducting qubits on 300 mm wafers

Abstract

We present the development of Nb/Al-AlOx/Nb trilayer stacks and implementation of a full 300 mm process flow for fabrication of trilayer-based superconducting qubits. Room temperature electrical characterization of tens of thousands of Josephson junctions showed good agreement between blanket resistance-area product and resistance-area product of processed wafers. Cross bridge Kelvin resistor structures with dimensions ranging from 200 nm to 1.2 μ"m" were tested and exhibited excellent yield and exceptionally low resistance variability down to <1%. This result is expected to translate to reduced qubit device variability and improved predictability of qubit transition frequencies at cryogenic temperatures.