Superconducting vias for routing electrical signals through substrates and their methods of manufacture
In a general aspect, a superconducting via for routing electrical signals through a substrate includes the substrate and a layer formed of superconducting material. The substrate has a first orifice disposed on a first surface and a second orifice disposed on a second surface. A cavity extends through the substrate from the first orifice to the second orifice. The layer of superconducting material includes a first portion occluding the first orifice and having an exterior surface facing outward from the substrate. The layer also includes a second portion in contact with a side wall of the cavity and extending to the second orifice. A quantum circuit element may optionally be disposed on the first surface and electrically coupled to the exterior surface of the first portion of the layer.
1. A superconducting via for routing electrical signals through a substrate, the via comprising:
the substrate, having a first surface and a second surface and comprising:
a first orifice disposed on the first surface,
a second orifice disposed on the second surface, and
a cavity extending from the first orifice to the second orifice, wherein the cavity is defined by non-parallel side walls that taper progressively along a direction from the second orifice to the first orifice, and the second orifice is larger than the first orifice;
a layer formed of superconducting material, the layer comprising:
a first portion occluding the first orifice and having an exterior surface facing outward from the substrate, and
a second portion in contact with the side walls of the cavity and extending to the second orifice; and
a support material formed of a polymeric material and configured to mechanically support the first portion of the layer from inside the cavity, the support material disposed on the layer within the cavity on a surface of the first portion opposite the exterior surface and on a surface of the second portion opposite the side walls of the cavity.
2. The via of claim 1 , comprising a quantum circuit element disposed on the first surface and electrically coupled to the exterior surface of the first portion of the layer.
3. The via of claim 1 , wherein the superconducting material has a superconducting critical temperature equal to or less than 40 K.
4. The via of claim 1 ,
wherein the layer comprises a first layer formed of a first superconducting material and a second layer formed of a second superconducting material;
wherein the first layer is in contact with the side wall of the cavity and comprises the exterior surface; and
wherein the second layer is disposed over the first layer.
5. The via of claim 1 ,
wherein the layer comprises a first layer formed of a first superconducting material, a second layer formed of a second superconducting material, and a third layer formed of a third superconducting material;
wherein the first layer is in contact with the side wall of the cavity and comprises the exterior surface;
wherein the second layer is disposed over the first layer; and
wherein the third layer is disposed over the second layer.
6. The via of claim 5 , wherein the support material is disposed over the third layer.
7. The via of claim 1 ,
wherein the layer comprises first and second layers, the first layer in contact with the side wall of the cavity and comprising the exterior surface, the second layer disposed over the first layer;
wherein the first and second layers are formed of, respectively, first and second superconducting materials having different compositions; and
wherein the first and second superconducting materials comprise aluminum, molybdenum, titanium, niobium, ruthenium, rhenium, tantalum, vanadium, zirconium, or any combination thereof.
8. The via of claim 1 , wherein the layer further comprises:
a third portion covering an area of the second surface and in contact therewith.
9. The via of claim 1 , wherein the polymeric material comprises one of parylene, polyimide, benzocyclobutene (BCB), or spin-on glass.
10. The via of claim 1 , wherein the support material is disposed on the surfaces of the first and second portions of the layer as a conformal layer.
11. An integrated quantum circuit, comprising:
a silicon substrate having a first planar surface disposed opposite a second planar surface and parallel thereto, the silicon substrate comprising:
a first orifice disposed on the first planar surface,
a second orifice disposed on the second planar surface,
a cavity extending from the first orifice to the second orifice along a longitudinal axis perpendicular to the first and second planar surfaces, wherein the cavity is defined by non-parallel side walls that taper progressively along a direction from the second orifice to the first orifice, and the second orifice is larger than the first orifice;
a layer formed of superconducting material, the layer comprising:
a first portion occluding the first orifice and having an exterior surface facing outward from the substrate, and
a second portion in contact with the side walls of the cavity and extending to the second orifice;
a support material formed of a polymer material and configured to mechanically support the first portion of the layer from inside the cavity, the support material disposed on the layer within the cavity on a surface of the first portion opposite the exterior surface and on a surface of the second portion opposite the side walls of the cavity; and
a quantum circuit element disposed on the first surface and comprising a Josephson junction, the quantum circuit element electrically coupled to the exterior surface of the first portion of the layer.
12. The integrated quantum circuit of claim 11 , wherein the superconducting material of the layer is titanium nitride.
13. The integrated quantum circuit of claim 11 , wherein the superconducting material of the layer is a niobium titanium nitride tertiary alloy.
14. The integrated quantum circuit of claim 11 ,
wherein the layer comprises a first layer formed of niobium and a second layer formed of an alloy of molybdenum and rhenium;
wherein the first layer is in contact with the side wall of the cavity and comprises the exterior surface;
wherein the second layer is disposed over the first layer; and
wherein the support material is disposed over the second layer.
15. The integrated quantum circuit of claim 11 ,
wherein the layer comprises a first layer formed of an alloy of molybdenum and rhenium, a second layer formed of niobium, and a third layer formed of the alloy of molybdenum and rhenium;
wherein the first layer is in contact with the side wall of the cavity and comprises the exterior surface;
wherein the second layer is disposed over the first layer;
wherein the third layer is disposed over the second layer; and
wherein the support material is disposed over the third layer.
16. The integrated quantum circuit of claim 11 ,
wherein the layer comprises first and second layers, the first layer in contact with the side wall of the cavity and comprising the exterior surface, the second layer disposed over the first layer;
wherein the first and second layers are formed of, respectively, first and second superconducting materials having different compositions; and
wherein the first and second superconducting materials comprise aluminum, molybdenum, titanium, niobium, ruthenium, rhenium, tantalum, vanadium, zirconium, or any combination thereof.
17. The integrated quantum circuit of claim 11 , wherein the layer further comprises:
a third portion covering an area of the second surface and in contact therewith.
18. The integrated quantum circuit of claim 11 , wherein the polymeric material comprises one of parylene, polyimide, benzocyclobutene (BCB), or spin-on glass.
19. The integrated quantum circuit of claim 11 , wherein the support material is disposed on the surfaces of the first and second portions of the layer as a conformal layer.