Characterization of sputtered hafnium thin films for high quality factor microwave kinetic inductance detectors. (arXiv:2004.00736v1 [physics.ins-det])

Characterization of sputtered hafnium thin films for high quality factor microwave kinetic inductance detectors. (arXiv:2004.00736v1 [physics.ins-det])
<a href="http://arxiv.org/find/physics/1/au:+Coiffard_G/0/1/0/all/0/1">G. Coiffard</a>, <a href="http://arxiv.org/find/physics/1/au:+Daal_M/0/1/0/all/0/1">M. Daal</a>, <a href="http://arxiv.org/find/physics/1/au:+Zobrist_N/0/1/0/all/0/1">N. Zobrist</a>, <a href="http://arxiv.org/find/physics/1/au:+Swimmer_N/0/1/0/all/0/1">N. Swimmer</a>, <a href="http://arxiv.org/find/physics/1/au:+Steiger_S/0/1/0/all/0/1">S. Steiger</a>, <a href="http://arxiv.org/find/physics/1/au:+Bumble_B/0/1/0/all/0/1">B. Bumble</a>, <a href="http://arxiv.org/find/physics/1/au:+Mazin_B/0/1/0/all/0/1">B. A. Mazin</a>

Hafnium is an elemental superconductor which crystallizes in a hexagonal
close packed structure, has a transition temperature $T_{C} simeq 400 mK$, and
has a high normal state resistivity around $90 mu Omega. cm$. In Microwave
Kinetic Inductance Detectors (MKIDs), these properties are advantageous since
they allow for creating detectors sensitive to optical and near infra-red
radiation. In this work, we study how sputter conditions and especially the
power applied to the target during the deposition, affect the hafnium $T_{C}$,
resistivity, stress, texture and preferred crystal orientation. We find that
the position of the target with respect to the substrate strongly affects the
orientation of the crystallites in the films and the internal quality factor,
$Q_{i}$, of MKIDs fabricated from the films. In particular, we demonstrate that
a DC magnetron sputter deposition at a normal angle of incidence, low pressure,
and low plasma power promotes the growth of compressive (002)-oriented films
and that such films can be used to make high quality factor MKIDs with $Q_{i}$
up to 600,000.

Hafnium is an elemental superconductor which crystallizes in a hexagonal
close packed structure, has a transition temperature $T_{C} simeq 400 mK$, and
has a high normal state resistivity around $90 mu Omega. cm$. In Microwave
Kinetic Inductance Detectors (MKIDs), these properties are advantageous since
they allow for creating detectors sensitive to optical and near infra-red
radiation. In this work, we study how sputter conditions and especially the
power applied to the target during the deposition, affect the hafnium $T_{C}$,
resistivity, stress, texture and preferred crystal orientation. We find that
the position of the target with respect to the substrate strongly affects the
orientation of the crystallites in the films and the internal quality factor,
$Q_{i}$, of MKIDs fabricated from the films. In particular, we demonstrate that
a DC magnetron sputter deposition at a normal angle of incidence, low pressure,
and low plasma power promotes the growth of compressive (002)-oriented films
and that such films can be used to make high quality factor MKIDs with $Q_{i}$
up to 600,000.

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