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

Abstract

Abstract We present the development of Nb/Al–AlO x /Nb trilayer stacks and the implementation of a full 300 mm process flow for the fabrication of trilayer-based superconducting qubits. Room temperature electrical characterization of tens of thousands of Josephson junctions showed good agreement between blanket resistance-area (RA) product and RA product of processed wafers. Cross-bridge Kelvin resistor structures with dimensions ranging from 200 nm to 1.2 μm 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.