电容读出式非制冷红外焦平面阵列设计

摘要

With the aim to improve the performance of an infrared detector and to enhance the characteristics of a Focal Plane Array(FPA), a capacitive-read infrared FPA with the structure of cantilever element in a fold-line leg and a long-line leg was designed. The thermal conductivity , thermo-mechanical sensitivity and the thermal time constant of the structure were discussed and optimized, then these parameters were set to be 3× 10-7 W/K, 162 nm/K and 35 ms, respectively. The sensitivity of design is fast enough to satisfy the requirements of human eyes. Furthermore, the Noise Equivalent Temperature Difference(NETD) which is key for the FPA detection was discussed, and calculated result shows that the NETD of the designed FPA is 6 mK. A simulation for the NETD was also performed,which shows the NETD is 5 mK. Experiments indicate that the simulation result agrees with that of the calculation well and show that the NETD is small enough to satisfy the resolution for signal readout. Finally, the capacitive-read FPA was fabricated based on silicon micromachining technology successfully.%设计了一种长支腿式电容读出式红外焦平面阵列结构,并分析了这种像元结构的热导率、热机械灵敏度和热时间常数,从中优化出了该模型的部分结构参数,并以此为依据对像元整体尺寸进行了设计.在该尺寸模型下,得到的像元热导率为3×10-7W/K,热机械灵敏度为162 nm/K,热时间常数为35 ms,该热时间常数满足人眼识别频率的需要.讨论了焦平面阵列能够高灵敏度工作的关键参数-噪声等效温差,分析计算显示,得到噪声等效温差为6 mK.进行了仿真计算,得到的噪声等效温差为5 mK,与计算结果非常吻合.实验表明,该系统的噪声等效温差足够小,可满足稳定输出信号的需要.最后,基于牺牲层工艺制备了长支腿结构焦平面阵列,验证了制备工艺的可行性.