Systems and methods for fabricating superconducting integrated circuits
Methods for mitigating microwave crosstalk and forming a component in a superconducting integrated circuit are discussed. Mitigating microwave crosstalk involves forming a microwave shield within the superconducting integrated circuit, the superconducting integrated circuit including a microwave sensitive component. The microwave shield is formed from a base layer and one or more sides, and the footprint of the microwave sensitive component is contained within the footprint of the microwave shielding base layer, with the one or more sides extending around at least a portion of the microwave sensitive component. Forming a component involves depositing a first metal layer, depositing a dielectric layer overlying the first metal layer, the dielectric layer comprising Nb 2 O 5 that is deposited by atomic layer deposition, and depositing a second metal layer overlying the dielectric layer.
1 . A method of mitigating microwave crosstalk in a superconducting integrated circuit, the superconducting integrated circuit comprising a microwave sensitive component, the microwave sensitive component having a footprint and being formed in multiple interconnected layers of the superconducting integrated circuit, the method comprising:
forming a microwave shielding base layer to at least partially shield the microwave sensitive component, the microwave shielding base layer having a footprint;
forming one or more sides extending from the microwave shielding base layer to at least partially shield the microwave sensitive component, including forming at least one shielding layer through multiple layers of the superconducting integrated circuit to at least partially enclose the microwave sensitive component; and
forming a dielectric material to surround the microwave sensitive component, the dielectric material disposed between the microwave shielding base layer and the microwave sensitive component and between the one or more sides and the microwave sensitive component, the dielectric material being a silicon compound;
wherein the footprint of the microwave sensitive component is contained within the footprint of the microwave shielding base layer and the one or more sides extend around at least a portion of the microwave sensitive component, and the microwave shielding base layer and the one or more sides form at least a portion of a microwave shield.
2 . The method of claim 1 , wherein forming a microwave shielding base layer to at least partially shield the microwave sensitive component comprises forming the microwave shielding base layer to underlie the microwave sensitive component.
3 . The method of claim 2 , further comprising: forming a microwave shielding top layer to at least partially shield the microwave sensitive component, the microwave shielding top layer overlying the microwave sensitive component, and the microwave shielding base layer, the one or more sides and the microwave shielding top layer form the microwave shield.
4 . The method of claim 3 , wherein forming the one or more sides comprises forming the one or more sides to connect the microwave shielding base layer and the microwave shielding top layer.
5 . The method of claim 3 , wherein forming the one or more sides comprises forming one or more vias.
6 . The method of claim 1 , wherein forming at least one of a microwave shielding base layer and one or more sides extending from the microwave shielding base layer comprises forming the at least one of a microwave shielding base layer and one or more sides from one or more of aluminum and niobium.
7 . The method of claim 1 , wherein forming at least one shielding layer through multiple layers of the superconducting integrated circuit to at least partially enclose the microwave sensitive component comprises forming the at least one shielding layer to have dimensions determined by thicknesses of corresponding wiring layers of the superconducting integrated circuit.
8 . The method of claim 1 , wherein forming at least one shielding layer through multiple layers of the superconducting integrated circuit to at least partially enclose the microwave sensitive component comprises forming one or more superconducting vias.
9 . The method of claim 1 , wherein forming the dielectric material to surround the microwave sensitive component includes forming a plurality of dielectric layers to surround the microwave sensitive component by the dielectric material.