一种与CMOS工艺兼容的热电堆红外探测器

报道了一种与CMOS工艺兼容的微机械热电堆红外探测器。提出了具有一对热电偶的两层悬浮结构,其占空因子达到80%以上,并采用P/N多晶硅作为热电偶材料,黑硅作为吸收层材料。给出了器件的工作原理,对性能优化与制作的工艺流程进行了分析,结合所选材料的基本参数,得到了优化后的结构尺寸。通过理论计算,可以获得响应率大于1000 V/W,探测率大于1×108cmHz1/2W-1,时间常数小于40ms,噪声等效温差小于30mK的性能优良的热电堆红外探测器。该器件的吸收层位于结构中的顶层,金属布线位于底层,便于与后续电路集成。单元大小为25 m×25 m,有利于制作非制冷红外焦平面阵列。

Fabrication of a Thermopile Infrared Detector That Compatible with CMOS Process

A kind of MEMS thermopile infrared detector that compatible with CMOS process is presented in this paper. The detector, whose fill factor is larger than 80%, has a suspension structure with one pair of thermopiles, with the black silicon as the absorption layer material and P/N polysilicon as the thermopiles material. The basic principle of the detector, optimum of detector performance and fabrication process is analyzed. With the selected material parameters, the optimal structure parameters are obtained. Through the theoretic calculation, a novel thermopile-based infrared detector is obtained, with good properties of high responsivity (larger than 1000 V/W) and detectivity (larger than 1×108 cmHz1/2W-1), and low time constant value (smaller than 40 ms) and NETD (smaller than 30 mK). The absorption layer locates in the upper layer of the detector; while the layer of metal layout locates in the bottom, which is easier to integrate with the read-out circuit layer. The pixel size is designed as 25 μm×25 μm, which is easier to be formed into an infrared focal plane array.