硅基PZT 热释电厚膜红外探测器的研制

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30 m 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1.510-8Ccm-2K-1。最后制备了敏感元为3 mm3 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7.4107 cmHz1/2W-1。

Preparation of Si-based PZT pyroelectric thick film infrared detector

Lead zirconate titanate (PbZr0.3Ti0.7O3) thick films and single element detectors for pyroelectric applications were fabricated on Si (100) substrates by MEMS and screen-printing technology. The preparation method and device processing technology were studied in detail. Firstly, the silicon-cup was etched by tetra-methyl ammonium hydroxide (TMAH) solution. Secondly, the Al2O3 barrier layer was prepared to prevent Si diffusion between PZT/ Si through reactive radio frequency (RF) sputtering. Cool isostatic pressing experiments were conducted in order to increase the density of PZT thick films. Finally, the PZT ceramic thick films about 30 m were achieved at a low sintering temperature about 850 ℃. The dielectric permittivity and loss angle tangent tested at 1 kHz under 25℃ were 210 and 0.017 respectively. By using dynamic current method, pyroelectric coefficient of the PZT thick film was determined to be 1.5 10 -8 Ccm-2K-1. The detectivity of detector with 3 mm3 mm area was measured by mechanically chopped blackbody radiation as the function of frequency. The results show that the single element detector obtains its maximum detectivity 7.4107 cmHz1/2W-1 at 112.9 Hz.