Multiphysics simulation of hypersensitive microbolometer sensor using vanadium dioxide and air suspension for millimeter wave imaging
Multiphysics simulation of hypersensitive microbolometer sensor using vanadium dioxide and air suspension for millimeter wave imaging
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DOI：
10.1007/s00542-020-05031-0
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发表时间：
2020-09
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影响因子：
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通讯作者：
Shangyi Chen;M. Lust;N. Ghalichechian
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文献类型：
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作者：
Shangyi Chen;M. Lust;N. Ghalichechian
本文报道了一种用于毫米波（mmW）成像的高灵敏度非制冷天线耦合微测辐射热计。我们的设计中采用了二氧化钒 (VO2) 相变材料，以利用其电阻率的非线性变化。所提出的微测辐射热计利用了 VO2 在非线性区域的大热阻系数 (TCR)。与非悬挂式微测辐射热计相比，通过微机电系统 (MEMS) 技术将器件悬挂在基板上方，器件的热阻得到显着改善。与具有电容滚降限制的半导体传感器不同，所提出的天线耦合传感器具有固有的高工作频率和适合毫米波成像器的宽带宽。采用有限元方法对装置的电热和电磁性能进行分析。工作频率范围为 65–85 GHz，宽边实现的增益为 > 1.0 dB。仿真结果表明，其响应度高达 1.72 × 103V/W，噪声等效功率 (NEP) 为 33 pW/√Hz。器件灵敏度的提高主要是由于 VO2 电阻率急剧变化的结果，并通过使用 MEMS 微加工工艺的空气悬浮来辅助。在这项工作中，我们首次使用多物理场建模展示了利用 VO2 的非线性行为来增强传统微测辐射热计的灵敏度。根据这项研究的结果，所提出的传感器的像素化阵列将能够实现用于各种传感应用的高灵敏度毫米波相机。
A highly sensitive uncooled antenna-coupled microbolometer for millimeter wave (mmW) imaging is reported in this paper. Vanadium dioxide (VO2) phase-change material is utilized in our design to exploit its non-linear change in electrical resistivity. The proposed microbolometer takes advantage of the large thermal coefficient of resistance (TCR) of VO2at the non-linear region. The thermal resistance of the device is significantly improved by micro-electro-mechanical systems (MEMS) techniques to suspend the device above the substrate, compared with non-suspended microbolometers. Unlike semiconductor-based sensors that are characterized by capacitive roll-off limitations, the proposed antenna-coupled sensor has an inherently high operating frequency and wide bandwidth suitable for mmW imagers. The finite element method is employed to analyze the electrothermal and electromagnetic performance of the device. The frequency range of operation is 65–85 GHz, and the realized gain at broadside is > 1.0 dB. Simulation results indicate a high responsivity of 1.72 × 103V/W and a low noise equivalent power (NEP) of 33 pW/√Hz. The enhanced device sensitivity is primarily the result of the sharp change in VO2′s electrical resistivity and is assisted by air suspension using MEMS microfabrication processes. In this work, for the first time, using multiphysics modeling we demonstrate exploitation of VO2′s non-linear behavior in enhancing the sensitivity of a conventional microbolometer. Based on the findings of this study, a pixilated array of the proposed sensors will enable the realization of a highly sensitive mmW camera for a variety of sensing applications.