Quartz microresonators for the high-resolution detection of infrared radiation

频率相关的谐振传感器适用于各种被测对象的高分辨率检测，例如，通过石英微量天平测量质量的最小变化，或使用石英谐振器测量时间。各种出版物表明，该原理也适用于温度测量，因此也适用于红外辐射的检测。高精度源于准数字输出频率的干扰独立性以及石英作为谐振器材料的优异、长期稳定的机电性能。因此，与其他红外探测器类型相比，噪声和其他干扰效应较低。这种谐振检测器的响应性（即，由温度变化引起的频率变化）与谐振频率成比例，谐振频率随着谐振结构的尺寸减小而增加。然而，限制因素是单晶石英的大尺寸（特别是石英厚度）。这导致低谐振频率，并且因此导致从检测器元件到周围环境的大热导值（与其它IR检测器相比）。虽然使用压电薄膜可以解决这个小型化问题，但多晶特性导致巨大的贡献过程，使得可实现的探测率将保持低于其他热红外传感器。因此，这里提出的项目的目标是创建3D结构，超薄（石英厚度< 5 µm）石英谐振器，具有薄膜器件的典型尺寸，但避免了多晶薄膜的缺点。结果，这种石英元件具有明显更小的热容和热导率，这提高了热分辨率和灵敏度以及检测率。为了减少热传导，检测器元件被设计成通过蚀刻沟槽自支撑和热绝缘。检测器系统的灵敏度的进一步增加通过引入晶体中的沟槽来实现。结果，石英振荡器的谐振频率由于较低的质量而增加。通过离子束蚀刻进行生产。最后，传感器元件的吸收率应该通过超薄纳米结构黑色层来增加。这些是通过相应的黑色层材料的掠射角蒸发产生的。通过分析模型和数值模拟，将得出设计准则，利用这些准则可以实现最大可能的探测率值。为了评估新的方法，示威者应构建和表征他们的敏感性和他们的噪音行为。

Frequency-dependent, resonant sensors are suitable for the high-resolution detection of a variety of measurands, e.g. for measuring smallest changes in mass by means of quartz microbalances or for time using quartz resonators. Various publications have shown that this principle is also suitable for the temperature measurement and, hence, for the detection of infrared radiation. The high accuracy results from the interference independence of the quasi-digital output frequency and the excellent, long-term stable electromechanical properties of quartz as resonator material. For that reason, noise and other interfering effects are low compared to other IR detector types. The responsibility (i.e. the change in frequency caused by temperature change) of such resonance detectors is proportional to the resonance frequency, which increases with decreasing size of the resonating structure. However, a limiting factor is the large dimension of the monocrystalline quartz (in particular quartz thickness). This results in low resonance frequencies and, thus, in large thermal conductance values (compared to other IR detectors) from the detector element to the surroundings. Although the use of piezoelectric thin films could solve this miniaturization problem, the polycrystalline properties lead to huge contributions processes so that the achievable detectivity would remain below that of other thermal IR sensors.Therefore, the goal of the project proposed here is to create 3D-structured, ultra-thin (quartz thickness < 5 µm) quartz resonators that have typical dimensions of thin-film devices but avoid the disadvantages of polycrystalline thin films. As a result, such quartz elements have significantly smaller heat capacities and thermal conductivities, which increases both the thermal resolution and the sensitivity as well as the detectivity. To reduce the thermal conductance, the detector element is designed to be self-supporting and thermally insulated by an etching trench. A further increase in sensitivity of the detector system is achieved by means of trenches which are introduced into the crystal. As a result, the resonant frequency of the quartz oscillator increases due to the lower mass. The production takes place by means of ion beam etching. Finally, the absorptivity of the sensor element should be increased by ultra-thin nanostructured black layers. These are produced by glancing angle evaporation of corresponding black layer materials. By means of analytical models and numerical simulations design guidelines are to be derived with which the greatest possible detectivity values can be achieved. To evaluate the novel approach, demonstrators should be constructed and characterized regarding their sensitivity and their noise behavior.