Superconducting TSV contact for cryoelectronic devices

TL;DR

This paper presents a fabrication process for niobium superconducting through-silicon vias (TSVs) that improves wall quality and enables superconducting coupling, advancing cryoelectronic device integration.

Contribution

It introduces a supercycle process in TSV fabrication that enhances wall quality and achieves superconducting coupling between strips.

Findings

Supercycle process improves TSV wall quality.

Superconducting coupling observed after 12 supercycles.

Critical current density of 5x10^4 A/cm^2 achieved.

Abstract

This work focuses on the fabrication of niobium through silicon vias (TSV) superconductors interconnects. The effect of supercycle of sequential oxidation and chemical etching process on the through-etch wall quality was investigated. It was experimentally shown that the use of supercycle in the fabrication process leads to significant improvement of the TSV wall quality and removal of the defect type - scallops. After 12 times repetitions of supercycles a dissipative bonding of superconducting strips on the front and back side of the sample is observed. The critical current density of such coupling is 5x104 A/cm2. The critical ratio of substrate thickness to hole diameter at which electrical coupling is formed is 3 : 1.