Fabrication of interlayer dielectrics with high quality interfaces for quantum computing devices

A method of fabricating a device comprising:

• providing a first wafer comprising a first substrate, a first insulator layer on the first substrate, and a first dielectric layer on the first insulator layer;
• providing a second wafer comprising a second substrate, a second insulator layer on the second substrate, and a second dielectric layer on the second insulator layer;
• forming a first superconductor layer on the first dielectric layer;
• forming a second superconductor layer on the second dielectric layer;
• joining a surface of the first superconductor layer to a surface of the second superconductor layer to form a wafer stack at an ambient temperature below approximately 150° C.;
• identifying an exposed first surface of the first dielectric layer;
• and
• forming a third superconductor layer on the exposed first surface of the first dielectric layer.