Future cosmic microwave background (CMB) experiments, including the large scale ground-based Stage Four CMB Experiment (CMB-S4), satellites, and balloons, aim to map the CMB to an unprecedented precision in order to answer several key questions in cosmology. However, to reach the target noise sensitivity, more than 100,000 detectors will be needed. Arrays of kinetic inductance detectors (KIDs) are a promising alternative for experiments that require large number of detectors due to the intrinsic multiplexing capabilities. We present the fabrication procedure for a prototype planar orthomode transducer (OMT)-coupled multi-color KID array optimized for 220/270 GHz frequency bands. These devices are made from silicon-on-insulator wafers to provide a low-loss substrate for the KIDs. The OMT couples the two polarizations of light from a wide-band feedhorn to separate Nb/SiN/Nb microstrip lines, which are then coupled to Al/Nb lumped-element KIDs (LEKIDs). The silicon on the backside of the OMT is etched away using deep reactive ion etch to release the OMT membrane to enable operation over a wide bandwidth. Finally, the buried oxide is removed underneath the KID capacitors in order to minimize two-level system noise and loss mitigation. We achieved a good yield (> 80%) on our prototype devices.

中文翻译：

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用于 CMB 检测的 OMT 耦合动感探测器的制作

未来的宇宙微波背景 (CMB) 实验，包括大规模地基第四阶段 CMB 实验 (CMB-S4)、卫星和气球，旨在以前所未有的精度绘制 CMB 地图，以回答宇宙学中的几个关键问题。然而，要达到目标噪声灵敏度，将需要超过 100,000 个检测器。由于固有的多路复用能力，动态电感检测器 (KID) 阵列是需要大量检测器的实验的一种有前途的替代方案。我们介绍了原型平面正交模式换能器 (OMT) 耦合多色 KID 阵列的制造过程，该阵列针对 220/270 GHz 频段进行了优化。这些器件由绝缘体上硅晶片制成，为 KID 提供低损耗基板。OMT 将来自宽带喇叭天线的两种偏振光耦合到分离的 Nb/SiN/Nb 微带线，然后耦合到 Al/Nb 集总元件 KID (LEKID)。OMT 背面的硅使用深度反应离子蚀刻来蚀刻掉，以释放 OMT 膜，从而能够在很宽的带宽上运行。最后，去除 KID 电容器下方的掩埋氧化物，以最大限度地减少两级系统噪声和损耗缓解。我们在原型设备上实现了良好的良率 (> 80%)。去除 KID 电容器下方的掩埋氧化物，以最大限度地减少两级系统噪声和损耗。我们在原型设备上实现了良好的良率 (> 80%)。去除 KID 电容器下方的掩埋氧化物，以最大限度地减少两级系统噪声和损耗。我们在原型设备上实现了良好的良率 (> 80%)。