20μm微测辐射热计的结构优化及性能研究

发布时间：2018-07-04 14:39

本文选题：微测辐射热计 + 20μm×20μm像元　；参考：《电子科技大学》2015年硕士论文

【摘要】：微测辐射热计作为一种非制冷红外探测器,因为其功耗低,便于携带,性能优良,价格低廉等优点而广泛应用到军事和民用等市场。目前非制冷红外器件越来越朝着大规模高密度红外焦平面探测器的凝视方向发展,像元大小从较早的65μm×65μm到现在的15μm×15μm左右,像元结构也由传统的的单层L型结构到目前的双层伞形,双层S型,甚至三层结构发展。由于受制于国外技术和设备的封锁,20μm及以下器件在国内报道极少,且考虑到本实验室的工艺条件,本文研究像元尺寸定为20μm×20μm,像元结构则选择目前市场上应用广泛的单层L型,双层伞形,双层S型微测辐射热计。本文采用专业的微机电系统(MEMS)软件Intellisuite分别建立了像元大小为20μm×20μm单层L型,双层伞形,双层S型三种微测辐射热计的三维有限元分析模型。在此基础上,利用数学仿真软件Matlab建立了上述三种结构的红外吸收模型。以高性能指标(在60 Hz帧频下,NETD小于50 mk时对应的热导在10-8W/K量级,热时间常数小于8 ms)为参考,对三种结构分别进行了光学性能仿真以及器件理论热导计算,通过优化各层膜厚,上下谐振腔高度等参数,获得了较好的光学性能以及较小的器件热导。随后本文对三种结构的三维模型进行了力学性能优化设计,通过调整各材料的内应力、膜厚、谐振腔高度等参数,将器件的形变量控制在一个较小的范围内,研究发现影响其力学平衡的主要因素是支撑层和钝化层,它们对结构的力学性能起主要支撑作用。以这三种结构的光学性能,力学性能,以及热导研究为依据,确定了上述三种微测辐射热计的结构参数。随后再对三种结构进行了动态热学有限元仿真,研究了其器件热导和热时间常数;而微测辐射热计工作时,是需要加载偏置的,本文首次模拟了三种结构的实际工作状态,对其进行了热电耦合性能仿真,研究了其有效热导和热时间常数;在此研究基础上,分析了器件热导、有效热导,偏置电流的关系,根据高性能指标的要求,推出了其电流范围。通过加载不同的电流和相同的热辐射对器件进行热电耦合有限元仿真,考虑到热时间常数,有效热导和电压阈值,可获得三种结构各自的最优化电流
[Abstract]:As a kind of uncooled infrared detector, microbolometer is widely used in military and civil markets because of its advantages of low power consumption, easy to carry, good performance and low price. At present, uncooled infrared devices are becoming more and more oriented towards the staring direction of large-scale high-density infrared focal plane detectors. The pixel size ranges from 65 渭 m 脳 65 渭 m to about 15 渭 m 脳 15 渭 m. The pixel structure is also developed from the traditional single-layer L-type structure to the present double-layer umbrella-shaped, double-layer S-shaped and even three-layer structures. Because there are very few reports in China about the blockage of 20 渭 m and less devices restricted by foreign technology and equipment, and considering the technological conditions of our laboratory, the size of the pixel is set at 20 渭 m 脳 20 渭 m, and the pixel structure chooses the single layer L type, which is widely used in the market at present. Double-layer umbrella, double-layer S-type microbolometer. In this paper, three dimensional finite element analysis models of 20 渭 m 脳 20 渭 m single-layer L-type, double-layer umbrella-shaped and double-layer S-type microbolometer are established by using Intellisuite, a special MEMS software. On this basis, the infrared absorption model of the above three structures is established by using the mathematical simulation software Matlab. With the reference of high performance index (the corresponding thermal conductivity is 10 ~ (-8) W / K and the thermal time constant is less than 8 Ms when the NETD is less than 50 mk at 60 Hz frame rate), the optical performance simulation and the theoretical thermal conductivity calculation of the three structures are carried out respectively. By optimizing the parameters such as the thickness of each layer and the height of the upper and lower resonators, the better optical properties and the smaller thermal conductivity of the devices are obtained. In this paper, the mechanical properties of the three kinds of structures are optimized. By adjusting the internal stress, the thickness of the film and the height of the resonator, the deformation of the device is controlled in a small range. It is found that the main factors affecting the mechanical equilibrium of the structure are the supporting layer and the passivating layer, which play a major supporting role in the mechanical properties of the structure. Based on the optical properties, mechanical properties and thermal conductivity of the three structures, the structural parameters of the three microbolometers are determined. Then the dynamic thermal finite element simulation of the three structures is carried out, and the thermal conductivity and thermal time constants of the three structures are studied, while the load bias is required for the work of the microbolometer, and the actual working state of the three structures is simulated for the first time in this paper. The effective thermal conductivity and thermal time constant are studied, and the relationship among thermal conductivity, effective thermal conductivity and bias current of the device is analyzed, according to the requirements of high performance index, the thermal conductivity and thermal time constant of the device are simulated, and the relationship between thermal conductivity, effective thermal conductivity and bias current of the device is analyzed according to the requirements of the high performance index. The current range is deduced. The thermoelectric coupling finite element simulation of the device is carried out by loading different current and the same thermal radiation. Considering the thermal time constant, effective thermal conductivity and voltage threshold, the optimal current of each of the three structures can be obtained.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN215

【共引文献】