Ion-Beam-Assisted Deposition of Mo Thin Films for TES Applications

Morgan, Kelsey M.; Jaeckel, Felix T.; Kripps, Kari L.; McCammon, D.

doi:10.1109/tasc.2014.2384994

Cited by 9 publications

(7 citation statements)

References 18 publications

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“…The result of roughness R q (root mean surface squared roughness) is plotted vs. annealing temperature as shown in Figure 5. When the annealing temperature is below 300 • C, the R q is around 0.6 nm, which is similar or better than in previous work [7,12,15,20,30], as shown in Table 1. With good morphological property (lower roughness), the thin films present better performance in proximity effect and robust process compatibility in further TES fabrication with the multilayer readout wiring.…”

Section: Morphology Of Interface Compositionsupporting

confidence: 84%

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Influence of the Interface Composition to the Superconductivity of Ti/PdAu Films

Rajteri

et al. 2020

Nanomaterials

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In this work, the interface composition of the superconducting Ti/PdAu bilayer is tuned by an annealing process in N2 from 100 to 500 °C to control the superconducting transition temperature (Tc). This Ti-PdAu composition layer is characterized with a high-resolution transmission electron microscopy (HRTEM) and energy-dispersive spectrometer (EDS) to show the infiltration process. The surface topography, electrical, and cryogenic properties are also shown. The inter-infiltration of Ti and PdAu induced by the thermal treatments generates an intermixed layer at the interface of the bilayer film. Due to the enforced proximity effect by the annealing process, the Tc of Ti (55 nm)/PdAu (60 nm) bilayer thin films is tuned from an initial value of 243 to 111 mK which is a temperature that is suitable for the application as the function unit of a superconducting transition edge sensor.

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Section: Morphology Of Interface Compositionsupporting

confidence: 84%

“…The T c of pure Ti is from 360 to 500 mK [7][8][9][10][11] as the thicknesses changes. However, for a better ∆E, the T c should be ≈ 100 mK [12][13][14][15][16][17]. The tunable range of T c of a pure Ti film is limited.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Interface Composition to the Superconductivity of Ti/PdAu Films

Rajteri

et al. 2020

Nanomaterials

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“…We have previously reported on Mo films fabricated using ion-beam assisted e-beam evaporation 6 . A commercial end-Hall ion source is used in a cryo-pumped e-beam evaporator to deliver sufficiently high ion doses at low energy.…”

Section: Ion-beam Assisted Deposition Of Mo Filmsmentioning

confidence: 99%

“…Film stress showed a complex dependence on both ion energy and dose. Both tensile and compressive stresses can be produced, with higher ion energy and dose both leading to higher compressive stress 6 due to the atomic peening effect of ion beam 7 .…”

Section: Ion-beam Assisted Deposition Of Mo Filmsmentioning

confidence: 99%

Fabrication of Superconducting Mo/Cu Bilayers Using Ion-Beam-Assisted e-Beam Evaporation

et al. 2016

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Superconducting/normal metal bilayers with tunable transition temperature are a critical ingredient to the fabrication of high performance transition edge-sensors (TES). Popular material choices include Mo/Au and Mo/Cu, which exhibit good environmental stability and provide low resistivity films to achieve adequate thermal conductivity. The deposition of high quality Mo films requires sufficient adatom mobility, which can be provided by energetic ions in sputter deposition, or by heating the substrate in an e-beam evaporation process. The bilayer Tc depends sensitively on the exact deposition conditions of the Mo layer and the superconducting/normal metal interface. Because the individual contributions (strain, crystalline structure, contamination) are difficult to disentangle and control, reproducibility remains a challenge. Recently, we have demonstrated that low energy ion beam assist during e-beam evaporation offers an alternative route to reliably produce high quality Mo films without the use of substrate heating. The energy and momentum delivered by the ion beam provides an additional control knob to tune film properties such as resistivity and stress. In this report we describe modifications made to the commercial end-Hall ion-source to avoid iron contamination allowing us to produce superconducting Mo films. We show that the ion beam is effective at enhancing the bilayer interface transparency and that bilayers can be further tuned to reduced Tc and higher conductivity by vacuum annealing.

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“…Rather than build a hybrid chamber with multiple deposition methods, researchers have found solutions employing standard deposition systems. The limitations of evaporated Mo have been bypassed by either heating the sample substrate to > 500 • C [24] or incorporating an ion-beam to increase Mo atom energy [25]. Another solution has been to sputter a thin Au capping layer over a sputtered Mo film, breaking vacuum, and then evaporating high-quality Au for the remainder of the bilayer [26].…”

Section: Introductionmentioning

confidence: 99%

Development of a transition-edge sensor bilayer process providing new modalities for critical temperature control

Weber

Morgan

Yan

et al. 2020

Supercond. Sci. Technol.

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Transition-edge sensors (TESs) are thermal detectors in which a superconducting film that is electrically biased in the superconducting-to-normal transition is used as a thermometer. In most TESs, the film is a superconductor-normal metal bilayer where the two materials and their thicknesses are chosen to achieve various specifications including the transition temperature Tc . Traditionally, the materials in the bilayer are deposited in sequence without breaking vacuum in order to achieve a clean, uniform bilayer interface at the wafer-scale. This approach leads to constraints in material properties, fabrication techniques and, ultimately, TES designs. To overcome these constraints, we have developed a bilayer fabrication process that allows the layers to be deposited and patterned separately with an exposure to atmosphere between the deposition steps. We demonstrate better than 6% transition-temperature uniformity across a 7.6 cm (3 in) substrate and present satisfactory spectra from TES x-ray detectors fabricated in this fashion. We show how the new hybrid additive-subtractive TES fabrication process creates new design possibilities, including broad tuning of Tc across a substrate with a single bilayer thickness.

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Ion-Beam-Assisted Deposition of Mo Thin Films for TES Applications

Cited by 9 publications

References 18 publications

Influence of the Interface Composition to the Superconductivity of Ti/PdAu Films

Influence of the Interface Composition to the Superconductivity of Ti/PdAu Films

Fabrication of Superconducting Mo/Cu Bilayers Using Ion-Beam-Assisted e-Beam Evaporation

Development of a transition-edge sensor bilayer process providing new modalities for critical temperature control

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