Trilayer josephson junction structure with small air bridge and no interlevel dielectric for superconducting qubits

摘要

A technique relates to a trilayer Josephson junction structure. A dielectric layer is on a base electrode layer that is on a substrate. A counter electrode layer is on the dielectric layer. First and second counter electrodes are formed from the counter electrode layer. First and second dielectric layers are formed from the dielectric layer. First and second base electrodes are formed from base electrode layer. The first counter electrode, first dielectric layer, and first base electrode form a first stack. The second counter electrode, second dielectric layer, and second base electrode form a second stack. A shunting capacitor is between first and second base electrodes. An ILD layer is deposited on the substrate, the first and second counter electrodes, and the first and second base electrodes. A contact bridge connects the first and second counter electrodes. An air gap is formed underneath the contact bridge by removing ILD.

主权项

1. A method of forming a trilayer Josephson junction structure, the method comprising:
depositing a dielectric layer on a base electrode layer, wherein the base electrode layer is deposited on a substrate; depositing a counter electrode layer on the dielectric layer; forming a first counter electrode and a second counter electrode from the counter electrode layer; forming a first dielectric layer and a second dielectric layer from the dielectric layer; forming a first base electrode and a second base electrode from the base electrode layer, wherein the first counter electrode, the first dielectric layer, and the first base electrode form a first stack, wherein the second counter electrode, the second dielectric layer, and the second base electrode form a second stack, and wherein a shunting capacitor is formed between the first base electrode and the second base electrode; depositing conformally an inter-level dielectric layer on a top surface of the substrate, the first and second counter electrodes, and the first and second base electrodes; forming a contact bridge connecting the first counter electrode and the second counter electrode, after planarizing the inter-level dielectric layer to expose tops of the first and second counter electrodes; and forming an air gap underneath the contact bridge by removing the inter-level dielectric layer.