Paper Abstract and Keywords |
Presentation |
2021-01-19 13:30
Thermal Conductance of Tri-layer Membranes for Multi-Pixel Gamma-Ray Transition Edge Sensors Takahiro Kikuchi, Satoshi Kohjiro, Ryota Hayakawa, Go Fujii, Fuminori Hirayama, Masahiro Ukibe (AIST), Ryan Smith, Masashi Ohno (U-Tokyo) SCE2020-18 |
Abstract |
(in Japanese) |
(See Japanese page) |
(in English) |
We have been developing the Gamma-ray Transition Edge Sensors (TESs) which is able to achieve high energy resolution. Multi-pixel TESs are expected to increase count rate obtained by the conventional single pixel. To operate the multi-pixel TESs, characteristics on every pixels should be uniform. Thermal conductance of silicon-nitride (SixNy) membrane has been studied by many institutes in ages. They have adopted the SixNy membranes for TESs. However, the thin SixNy membrane has possibility to cause the space distribution of its thickness and stress due to inevitable space-distribution of etching speed of the silicon (Si) substrate by Deep Reactive Ion Etching (D-RIE). It is resulting in non-uniform characteristics among pixels. Silicon dioxide (SiO2) has been known to have stronger tolerance against the etching plasma. We have been fabricating the tri-layer membrane (SiO2/SixNy/SiO2) to overcome this problem. Total thickness of this tri-layer membrane is set to be about 7 um for adjusting membrane stress. The tri-layer membrane has been expected to have strong mechanical strength. Thermal conductance of the tri-layer membrane was ~1 nW/K although it was thicker than that of typical SixNy membrane thickness (~1 um). We confirmed that critical temperature of TES was not changed after D-RIE. This result means that the tri-layer membrane protects the superconducting film. Analyzing the membrane size dependence of joule power which needs to operate the TESs, we found thermal transport of phonons passing through the tri-layer membrane was between “ballistic” and “diffusive” regimes. The phonon-mean-free-path was about 1 um. |
Keyword |
(in Japanese) |
(See Japanese page) |
(in English) |
Gamma Ray / Membrane / Thermal Conductance / SixNy / SiO2 / Transition Edge Sensor / / |
Reference Info. |
IEICE Tech. Rep., vol. 120, no. 313, SCE2020-18, pp. 7-12, Jan. 2021. |
Paper # |
SCE2020-18 |
Date of Issue |
2021-01-12 (SCE) |
ISSN |
Online edition: ISSN 2432-6380 |
Copyright and reproduction |
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SCE2020-18 |