Magnetic field robust high quality factor NbTiN superconducting microwave resonators

Abstract

We systematically study the performance of compact lumped element planar microwave $\mathrm{Nb_{70}Ti_{30}N}$ (NbTiN) resonators operating at 5 GHz in external in-plane magnetic fields up to 440 mT, a broad temperature regime from 2.2 K up to 13 K, as well as mK temperatures. For comparison, the resonators have been fabricated on thermally oxidized and pristine, (001) oriented silicon substrates. When operating the resonators in the multi-photon regime at $T=2.2$ K, we find internal quality factors $Q_{\mathrm{int}}\simeq$ $2\cdot10^5$ for NbTiN resonators grown on pristine Si substrates. In addition, we investigate the $Q$-factors of the resonators on pristine Si substrates at millikelvin temperatures to asses their applicability for quantum applications. We find $Q_{\mathrm{int}}\simeq$ $2\cdot10^5$ in the single photon regime and $Q_{\mathrm{int}}\simeq$ $5\cdot10^5$ in the high power regime at $T=7$ mK. From the excellent performance of our resonators over a broad temperature and magnetic field range, we conclude that NbTiN deposited on Si (100) substrates, where the suface oxide has been removed, constitutes a promising material platform for electron spin resonance and ferromagnetic resonance experiments using superconducting planar microwave resonators.

Superconducting nitridized-aluminum thin films

“…those manipulating electron spins [39] or hybrid superconductorsemiconductor structures [58]. The behavior of NitrAl thin films under strong magnetic fields is comparable to that displayed in general by disordered superconductors, including grAl [59], NbN [47], and NbTiN [60].…”

Low-loss α-tantalum coplanar waveguide resonators on silicon wafers: fabrication, characterization and surface modification

“…Historically, several approaches have been explored to increase their performance such as, participation ratio engineering [3]-typically resulting in bigger qubits-as well as optimal control [4,5], shielding [6] and signal filtering [7]. In contrast, the number of advancements based on understanding microscopic origin of decoherence and energy loss-including the judicious increase of the materials toolbox-is rather limited [8,9], with most published work focusing on only a few well documented materials such as Al [10][11][12][13][14][15], Nb [16][17][18][19][20], TiN [21,22], NbN [23,24], NbTiN [25][26][27], granular-Al [28,29], Re [30] and In [31]. Only recently, the suite of materials for superconducting quantum technology was further expanded, markedly resulting in qubit relaxation times as high as 0.5 ms for 2D transmon qubits by using α-tantalum (α-Ta) [32,33].…”

Performance of high impedance resonators in dirty dielectric environments

“…Understanding the origin of dielectric losses is crucial when exploiting superconducting resonators for quantum information science. But studies of dielectric losses in various dielectrics have so far been based on low-impedance resonators [1][2][3][4][5][6][7][8][9]. However, a large resonator impedance is desirable, in-particular in the context of spin-qubits, as the coupling to a weak electric dipole moment scales with the square root of the impedance [10].…”