Self-shunted Nb/AlOx/Nb Josephson junctions
نویسندگان
چکیده
We describe the fabrication and properties of high critical current density (Jc) Nb/AlOx/Nb Josephson junctions with deep-submicron dimensions. The junctions are fabricated using a planarized process in which all levels are patterned using a combination of optical and electron beam lithography. The base and counter electrodes are defined by reactive ion etching using quartz etch masks to give a minimum feature size of 0.2 microns. For Jc = 2.1 mA/μm and junction area less than 0.1 μm the devices are self-shunted and exhibit nonhysteretic IV characteristics. A small hysteresis in the larger junctions is caused by heating in the electrodes.
منابع مشابه
Josephson junctions and DC SQUIDS based on Nb/Al technology.
A process for fabricating high-quality Josephson junctions and DC SQUIDs on basis of Nb/Al technology has been developed. DC magnetron sputtering is used for the deposition of the metal layers and the barrier is formed by thermal oxidation of the Al-layer. The junction area of 5 microns x 5 microns is obtained using anodisation. Three types of Josephson tunnel junctions have been prepared: stan...
متن کاملComplex Dynamics of Resistively and Inductively Shunted Josephson Junctions
We have measured Nb−AlOx −Nb Josephson tunnel junctions which have resistive shunts with different parasitic inductances. Numerical simulations reveal that specific features in the experimental current-voltage characteristics of these devices are DC signatures of complex AC behavior. Depending on the inductance of the shunt loop and the capacitance of the junction, these features may either app...
متن کاملNiobium-Silicide Junction Technology for Superconducting Digital Electronics
We present a technology based on Nb/NbxSi1−x/Nb junctions, with barriers near the metal-insulator transition, for applications in superconducting electronics (SCE) as an alternative to Nb/AlOx/Nb tunnel junctions. Josephson junctions with co-sputtered amorphous Nb-Si barriers can be made with a wide variety of electrical properties: critical current density (Jc), capacitance (C), and normal res...
متن کاملFabrication Process and Properties of Fully- Planarized Deep-Submicron Nb/Al-AlOx/Nb Josephson Junctions for VLSI Circuits
A fabrication process for Nb/Al-AlOx/Nb Josephson junctions (JJs) with sizes down to 200 nm has been developed on a 200-mm-wafer tool set typical for CMOS foundry. This process is the core of several nodes of a roadmap for fully-planarized fabrication processes for superconductor integrated circuits with 4, 8, and 10 niobium layers developed at MIT Lincoln Laboratory. The process utilizes 248 n...
متن کاملImproved Critical-Current-Density Uniformity of Nb Superconducting Fabrication Process Using Anodization Personnel
cross-wafer standard deviation of Jc was typically ~ 5% for anodized wafers but was ≥15% for unanodized wafers (Figure 6). A low variation in Jc results in a higher yield of device chips per wafer with the desired current density. As a result of the improved cross-wafer distribution, the cross-chip uniformity is greatly improved as well; typically < 1% for anodized chips. Low cross-chip Jc vari...
متن کامل