Brown A D, Brekosky R P, Colazo-Petit F, Greenhouse M A, Hays-Wehle J P, Kutyrev A S, Mikula V, Rostem K, Wollack E J, Moseley S H
NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
SSAI, Lanham, MD 20706 USA.; NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
IEEE Trans Appl Supercond. 2021 Aug;31(5). doi: 10.1109/tasc.2021.3065922. Epub 2021 Mar 12.
Excess heat capacity in a bolometric detector has the consequence of increasing or leading to multiple device time constants. The Mo/Au bilayer transition edge sensor (TES) bolometric detectors initially fabricated for the high resolution mid-infrared spectrometer (HIRMES) exhibited two response thermalization scales, one of which is a few times longer than estimates based upon the properties of the bulk materials employed in the design. The relative contribution of this settling time to the overall time response of the detectors is roughly proportional to the pixel area, which ranges between ~0.3 and 2.6 mm. Use of laser ablation to remove sections of the silicon membranes comprising the pixels results in a detector response with a smaller contribution from the secondary time constant. Additional information about the nature of this excess heat capacity is gleaned from glancing incidence x-ray diffraction, which reveals the presence of molybdenum silicides near the silicon surface which is a consequence of the bi-layer deposition. Quantitative analysis of the concentration of excess molybdenum, estimated with secondary ion mass spectroscopy, is commensurate to the additional heat capacity needed to explain the anomalous time response of the detectors.
测辐射热计探测器中的过剩热容量会导致器件时间常数增加或产生多个时间常数。最初为高分辨率中红外光谱仪（HIRMES）制造的钼/金双层过渡边传感器（TES）测辐射热计探测器表现出两种响应热化尺度，其中一种比基于设计中使用的块状材料特性的估计值长几倍。这种稳定时间对探测器整体时间响应的相对贡献大致与像素面积成正比，像素面积在约0.3至2.6平方毫米之间。使用激光烧蚀去除构成像素的硅膜部分，会使探测器响应中来自二次时间常数的贡献变小。通过掠入射X射线衍射可以收集到关于这种过剩热容量性质的更多信息，该衍射揭示了硅表面附近存在硅化钼，这是双层沉积的结果。用二次离子质谱法估计的过剩钼浓度的定量分析与解释探测器异常时间响应所需的额外热容量相符。
