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在(100)单晶Si衬底上,采用MEMS工艺和丝网印刷方法制作了锆钛酸铅(PZT)厚膜热释电红外探测器,深入研究了PZT厚膜材料的制备方法与器件加工工艺。采用四甲基氢氧化铵(TMAH)溶液腐蚀Si衬底制备硅杯结构。为防止Pb和Si相互扩散,在Pt底电极与SiO2/Si衬底之间通过射频反应溅射制备了Al2O3薄膜阻挡层。采用丝网印刷在硅杯中制备了30μm厚的PZT材料,并用冷等静压技术提高厚膜的致密度,实现了PZT厚膜在850℃的低温烧结。PZT厚膜在1 kHz、25℃下的相对介电常数与损耗角正切分别为210和0.017,动态法测得热释电系数为1.5×10-8Ccm-2K-1。最后制备了敏感元为3 mm×3 mm的单元红外探测器,使用由斩波器调制的黑体辐射,在调制频率为112.9 Hz时测得器件的探测率达到最大值7.4×107cmHz1/2W-1。
On the (100) single-crystal Si substrate, a lead zirconate titanate (PZT) thick film pyroelectric infrared detector was fabricated by using the MEMS technology and the screen printing method. The preparation method and device processing of the PZT thick film material were further studied Process. A silicon cup structure was prepared by etching the Si substrate with tetramethylammonium hydroxide (TMAH) solution. In order to prevent the mutual diffusion of Pb and Si, an Al2O3 film barrier layer was prepared by RF reactive sputtering between the Pt bottom electrode and the SiO2 / Si substrate. A 30μm thick PZT material was prepared by screen printing in a silicon cup, and the cold isostatic pressing technique was used to increase the density of the thick film. The PZT thick film was sintered at 850 ℃. The relative permittivity and loss tangent of PZT thick film at 210 kHz and 1 kHz respectively are 210 and 0.017, respectively. The pyroelectric coefficient of PZT thick film is 1.5 × 10-8Ccm-2K-1. Finally, a unitary infrared detector with a sensitivity of 3 mm × 3 mm was fabricated. Using black body radiation modulated by a chopper, the detection rate of the device reached a maximum of 7.4 × 107 cmHz1 / 2W-1 at a modulation frequency of 112.9 Hz .