Stress engineered microspring for cryogenic superconducting circuits

A structure, comprising:

• a microspring disposed on a build surface and comprising a film stack with a base and a spring member extending from the base;
• and
• the film stack comprising, in order from the build surface:
• a compressive layer having a first thickness;
• a substantially stress-free layer having a second thickness;
• and
• a tensile layer having a third thickness, wherein the second thickness is greater than the first and third thicknesses;
• wherein a stress gradient in the film stack causes the spring member to curl away from the build surface of the base.

A method of forming a microspring structure, comprising:

• depositing a sacrificial release layer over a substrate, the sacrificial release layer defining a build surface;
• depositing a film stack over the sacrificial release layer, the film stack comprising a compressive layer proximate the substrate, a tensile layer spaced from the substrate, and a substantially stress-free layer disposed between the compressive and tensile layers, the film stack formed of one or more materials that become superconducting below 140 K;
• patterning the film stack to define the microspring structure on the build surface, the microspring structure comprising a base and a spring member extending from the base;
• and
• removing a portion of the sacrificial release layer located under the spring member, such that stress within the film stack causes the spring member to curl out of the build surface.