Multilayer Strucrure with Zirconium-Oxide Tunnel Barriers and Applications of Same

John Ketterson (Inventor), Serhii Shafranjuk (Inventor)

Research output: Patent


Highly Homogeneous ZrOx Tunnel Barriers from Multi-step Deposition and Oxidation Inventors John Ketterson*, Oleksandr Chernyashevskyy, Ivan Nevirkovets Short Description Multilayered structure based on ZrOx through multi-step deposition and oxidization for robust, high performance superconducting and magnetic devices. #MATERIALS#Materials#electronics#Materials#semiconductor Abstract The tunnel barrier is an important component of superconducting and magnetic devices based on junctions utilizing electron tunneling. Most popular tunnel barrier materials, such as the aluminum oxides or magnesium oxides, are plagued by low melting temperature of the metal. In comparison, an oxide of ziroconium, i.e. ZrOx, is regarded as a promising alternative owning to its superior thermal stability. Nevertheless, conventional fabrication of ZrOx barrier relies on a single-step deposition and oxidization of Zr, which usually produces inhomogeneous oxide and the undesirable effect of high leakage current in the ultimate device. To overcome this problem, Northwestern researchers have developed highly homogenous ZrOx tunnel barriers using multi-step deposition and oxidation. In contrast to the one-step practice where a thick Zr overlayer is oxidized, Northwestern's novel fabrication multiply deposits very thin Zr layers to ensure the uniformity of ZrOx after oxidization. Significant performance improvement of the device using the novel multilayer ZrOx barrier has been demonstrated. This new technology enables the development of robust, high-performance devices based on the electron tunneling junctions, such as the superconducting Rapid Single-Flux Quantum electronics or magnetic random-access memory. Applications o Superconducting electronics o Magnetic random-access memory Advantages o High uniformity of oxide material in the tunnel barrier o Superior current-voltage characteristic, e.g. free of proximity-effect Publication: I. P. Nevirkovets, O. Chernyashevskyy and J. B. Ketterson, "Characteristics of Zr-based single- and multiple-barrier superconducting tunnel junctions", Appl. Phys. Lett. 88, 212504 (2006); IP Status US patent granted (US7977668). Marketing Contact Allan Nader, PhD Invention Manager (p): 847-491-4456 (e):
Original languageEnglish
Patent number7977668
StatePublished - Mar 5 2009


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