Superconducting niobium titanium nitride thin films deposited by plasma-enhanced atomic layer deposition

Abstract

NbTiN has a variety of superconducting applications, ranging from RF cavities to single-photon detectors. Here, we systematically investigated the plasma-enhanced atomic layer deposition (PEALD) of NbxTi with the organometallic precursors (t-butylimido) tris(diethyamido) niobium(V) and tetrakis (dimethylamido) titanium in conjunction with a remote H2/N2 plasma. Deposited film properties have been studied as a function of the ratio of Nb to Ti precursor pulses within each ALD supercycle. PEALD NbTiN films were characterized with spectroscopic ellipsometry (thickness, optical properties), four point probe (resistivity), x-ray photoelectron spectroscopy (composition), x-ray reflectivity (density and thickness), x-ray diffraction (crystallinity), and superconductivity measurements. The PEALD process has shown distinct advantages over deposition of superconducting films via thermal ALD or sputtering, for example a lower processing temperature and more efficient control of film composition. This control of film composition enabled the tuning of electrical and superconducting properties, such as varying the superconducting critical temperature TC between 6.9 and 13.2 K.

Effect of Large Lattice Mismatch on Superconductivity and Plasmonic Properties of Epitaxial NbTiN Films

“…As seen in Figure 4a, T c values are 15.1 and 15.9 K for NbTiN films on MgO and YAO substrates, respectively, which are higher than T c of most NbTiN films in previous reports (see Table 1). 6,11,19,20 where ω log is the logarithmically average phonon frequency, λ is the electron−phonon coupling constant, and μ* is the Coulomb pseudopotential. 22,23 Previous studies have also pointed out that in-plane compressive strain can suppress the electron−phonon coupling strength and T c in TiN.…”

Vertically-Aligned Multi-Walled Carbon Nano Tube Pillars with Various Diameters under Compression: Pristine and NbTiN Coated

“…Tris(diethylamido)(tert-butylimido) niobium (TBTDEN) and tetrakis(dimethylamino) titanium (TDMAT) were used as the niobium and titanium precursors and were maintained at 100 °C and 75 °C, respectively. The precursors were delivered to the system with a Boost TM system which introduces a charge of argon gas into the precursor cylinder before pulsing the precursor into the ALD reactor and substantially improving the transfer of low vapor pressure material from the cylinder to the substrate surface [ 46 ]. The ALD process consisted of repeated supercycles of precursor pulses and plasma exposure alternated with fixed purge periods.…”

A silicon‐organic hybrid platform for quantum microwave-to-optical transduction

“…One approach is to use high-kinetic inductance nanowires made of disordered superconductors such as NbN, TiN or NbTiN [61][62][63][64]. However, depositing high quality films from these materials is generally more challenging than evaporating aluminum, often requiring carefully tuned sputtering processes or atomic layer deposition [62,64,65]. A second approach is to use the kinetic inductance of an array of large Josephson junctions, where the Josephson energy E J of each individual junction is much larger than the charging energy E C [66,67].…”