Superconducting NbTiN Thin Films with Highly Uniform Properties over a 100 mm diameter Wafer

Abstract

Uniformity in thickness and electronic properties of superconducting niobium titanium nitride (NbTiN) thin films is a critical issue for upscaling superconducting electronics, such as microwave kinetic inductance detectors for submillimeter wave astronomy. In this article we make an experimental comparison between the uniformity of NbTiN thin films produced by two DC magnetron sputtering systems with vastly different target sizes: the Nordiko 2000 equipped with a circular 100mm diameter target, and the Evatec LLS801 with a rectangular target of 127 mm x 444.5 mm. In addition to the films deposited staticly in both systems, we have also deposited films in the LLS801 while shuttling the substrate in front of the target, with the aim of further enhancing the uniformity. Among these three setups, the LLS801 system with substrate shuttling has yielded the highest uniformity in film thickness (+/-2%), effective resistivity (decreasing by 5% from center to edge), and superconducting critical temperature (T_c = 15.0 K - 15.3 K) over a 100 mm diameter wafer. However, the shuttling appears to increase the resistivity by almost a factor of 2 compared to static deposition. Surface SEM inspections suggest that the shuttling could have induced a different mode of microstructural film growth.

Accepted 2016 November 21 for publication in IEEE Transactions on Applied Superconductivity, Applied Superconductor Conference 2016, 5 pages, 3 figures

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Cited by in corpus (7)

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• Terahertz Band-Pass Filters for Wideband Superconducting On-chip Filter-bank Spectrometers
• Suppression of radiation loss in high kinetic inductance superconducting co-planar waveguides
• Reactive magnetron sputter deposition of superconducting niobium titanium nitride thin films with different target sizes
• Volume dependence of microwave induced excess quasiparticles in superconducting resonators
• AMKID -- a large KID-based camera at the APEX telescope