Design and Fabrication of 90 GHz TES Polarimeter Detectors for the South Pole Telescope

Yefremenko, V.; Ade, Peter A. R.; Aird, K. A.; Austermann, J. E.; Beall, James A.; Becker, D.; Benson, B. A.; Bleem, L. E.; Britton, J.; Chang, C. L.; Carlstrom, J. E.; Cho, H.; Haan, T. de; Crawford, T. M.; Crites, A. T.; Datesman, A.; Dobbs, M.; Everett, W.; Ewall‐Wice, Aaron; George, E. M.; Halverson, N. W.; Harrington, N. L.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Hoover, S.; Hubmayr, Johannes; Irwin, K. D.; Keisler, R.; Kennedy, James E.; Lee, A.; Leitch, E. M.; Li, D.; Lueker, M.; Marrone, Dan; McMahon, Jeff; Mehl, J.; Meyer, S. S.; Montgomery, J.; Montroy, T. E.; Natoli, T.; Nibarger, J. P.; Niemack, Michael D.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, Christian; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schafer, K.; Shirokoff, E.; Story, K. T.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Williamson, A. R.; Yoon, K. W.; Young, E.

doi:10.1109/tasc.2012.2235892

Cited by 9 publications

(14 citation statements)

References 9 publications

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“…The fabrication of these devices is similar to the fabrication of SPTpol TES bolometers [22]. Using AJA DC magnetron sputtering system, Mo and Au films are sequentially deposited at room temperature without substrate heating on a 250 μm thick silicon wafer with 1 μm thick silicon nitride on surface.…”

Section: Devices and Measurementsmentioning

confidence: 99%

Mo/Au Bilayer TES Resistive Transition Engineering

Wang

Chang

Yefremenko

et al. 2015

IEEE Trans. Appl. Supercond.

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We have investigated two types of superconducting transition edge sensor (TES) modified with structures on the surface. One is a Mo/Au TES modified with Nb stripes, which increase the transition temperature and broaden the transition width. Another is a Mo/Au TES modified with Au stripes, which decrease the transition temperature and broaden the transition width. It is experimentally demonstrated that the resistive transition profile of a TES can be desirably engineered with a superconductor and/or a normal metal by properly choosing the width and spacing of the modification stripes on the surface.Index Terms-Bolometer, proximity effect, superconductivity, transition edge sensor.

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Section: Devices and Measurementsmentioning

confidence: 99%

Mo/Au Bilayer TES Resistive Transition Engineering

Wang

Chang

Yefremenko

et al. 2015

IEEE Trans. Appl. Supercond.

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“…Various groups worldwide have achieved performances approaching theoretical limits, but understanding the factors that determine the achieved performance remains a goal. TESs are currently used in ground-based telescopes such as EBEX, 3 SPTpol, 4 Keck/SPIDER, 5 and GISMO, 6 and will be used, or are proposed for use, in a number of upcoming space missions. 7,8 In its simplest form a TES consists of a superconducting thin-film (denoted here by S ′ ), typically ∼ 100 nm thick, operated very close to its superconducting transition temperature T c,S ′ .…”

Section: Introductionmentioning

confidence: 99%

“…These modifications reduce excess electrical noise 6 and change aspects of performance such as response times. 4,[9][10][11][12][13] In microcalorimeters normal-metal or semi-metal structures act as, or thermally couple to, photon absorbers. 14 Changes in the TES response time indicate a change in the small-signal electrothermal parameter α = (∂ ln R(T, I)/∂ ln T ) I , which characterizes the sharpness of the superconducting-normal resistive transition (here R is the TES resistance and I the bias current).…”

Section: Introductionmentioning

confidence: 99%

Modelling proximity effects in transition edge sensors to investigate the influence of lateral metal structures

Harwin¹,

Goldie²,

Withington³

2017

Supercond. Sci. Technol.

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The bilayers of Transition Edge Sensors (TESs) are often modified with additional normal-metal features such as bars or dots. Previous device measurements suggest that these features improve performance, reducing electrical noise and altering response times. However, there is currently no numerical model to predict and quantify these effects. Here we extend existing techniques based on Usadel's equations to describe TESs with normal-metal features. We show their influence on the principal TES characteristics, such as the small-signal electrothermal parameters α and β and the superconducting transition temperature Tc. Additionally, we examine the effects of an applied magnetic field on the device performance. Our model predicts a decrease in Tc, α and β as the number of lateral metal structures is increased. We also obtain a relationship between the length L of a TES and its critical temperature, Tc ∝ L −0.7 for a bilayer with normal-metal bars. We predict a periodic magnetic flux dependence of α, β and Ic. Our results demonstrate good agreement with published experimental data, which also show the reduction of α, β and Tc with increasing number of bars. The observed Fraunhofer dependence of critical current on magnetic flux is also anticipated by our model. The success of this model in predicting the effects of additional structures suggests that in the future numerical methods can be used to better inform the design of TESs, prior to device processing.

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“…In state-of-the-art far-infrared and millimeter TES detectors operating at sub-Kelvin temperatures [4,5,10], the beam length L is much larger than ℓ, and the thermal conductance is often described by the Fourier law for phonon diffusion, G(T ) = κ(T ) wt/L, where w and t are the width and thickness of the beam, and κ(T ) is the bulk thermal conductivity of the dielectric. κ(T )…”

Section: Introductionmentioning

confidence: 99%

“…However, this approach rarely provides a complete view of the thermal physics, and higher order effects such as surface roughness of the beams have been identified as the likely cause of the reported non-uniformity in G across detector arrays [4,5].…”

Section: Introductionmentioning

confidence: 99%

Precision control of thermal transport in cryogenic single-crystal silicon devices

Rostem

Chuss

Colazo

et al. 2014

Journal of Applied Physics

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We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path ℓ is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than ℓ, even when the surface is fairly smooth, 5-10 nm rms, and the peak thermal wavelength is 0.6 µm. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order ℓ, the conductance is dominated by ballistic transport and is effectively set by the beam area. We have demonstrated a uniformity of ±8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors. * Electronic address: karwan.rostem@nasa.gov

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Design and Fabrication of 90 GHz TES Polarimeter Detectors for the South Pole Telescope

Cited by 9 publications

References 9 publications

Mo/Au Bilayer TES Resistive Transition Engineering

Mo/Au Bilayer TES Resistive Transition Engineering

Modelling proximity effects in transition edge sensors to investigate the influence of lateral metal structures

Precision control of thermal transport in cryogenic single-crystal silicon devices

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