Deposition of high-quality ultra-thin NbN films at ambient temperatures
Paper i proceeding, 2014

This paper discusses the possibility of growing NbN ultra-thin films on Si-substrates and AlxGa1-xN buffer-layers by means of DC magnetron sputtering without intentional substrate heating. Resistance-temperature measurements were carried out and the superconducting properties such as Tc, ΔTc and R□ were deduced while HRTEM gave insight into the crystal structure and film thickness. The adjustment of the partial pressure of argon and nitrogen was found to be critical in establishing a reliable deposition process. The quality of the interface between the NbN film and the substrate was improved by optimizing the total pressure while sputtering, and is therefore particularly valuable for phonon-cooled HEB heterodyne receivers. NbN films of 5 nm thickness were obtained and exhibited a Tc from 8K on Si-substrates, and up to 10.5 K on the GaN buffer-layers. This result is significant since the absence of a high-temperature environment permits the establishment of more complex fabrication processes for intricate thin-film structures without compromising the overall integrity of e.g. dielectric layers, or hybrid circuitries with e.g. SIS junctions.

buffer-layer GaN

epitaxial ultra-thin NbN


Sascha Krause

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Vincent Desmaris

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Denis Meledin

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Victor Belitsky

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Mariusz Rudzinski

E. Pippel

25th International Sympsoium on Space Terahertz Technology, ISSTT 2014; Moscow; Russian Federation; 27 April 2014 through 30 April 2014



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