微桥结构PZT厚膜红外探测器研究

Study of PZT thick film infrared detector with micro-bridge structure

利用KOH溶液腐蚀结合SF6气体干法刻蚀工艺制备了锆钛酸铅(PbZr0.3Ti0.7O3,PZT)厚膜热释电红外探测器,得到了器件Si基背面完全悬空的微桥绝热结构。使用由斩波器调制的黑体辐射,测试了探测器在低频段的电压响应率、噪声等效功率和探测率等参数。结果表明,探测器在调制频率为5.3 Hz时的电压响应率约为4.5×102V/W;在调制频率为167.3 Hz时,其探测率达7.5×108 cm.Hz1/2/W;PZT厚膜探测器的热时间常数为51 ms,与PZT陶瓷器件相比小约一个数量级,有利于其在高频响应方面的应用。

A lead zirconate titanate （PbZr0.3Ti0.7O3,PZT） thick film pyroelectric infrared detector with micro-bridge thermal isolation structure was fabricated on Si substrate. The thermal isolation structure was fabricated by KOH wet etching and SF6 dry etching at the backside of the substrate. The voltage response rate, noise equivalent power and detectivity of the detector at low frequency were measured with blackbody radiation modulated by a chopper. The results show that the voltage response rate and detectivity of the detector reach their largest value （4.5×102 V/W and 7.5×108 cm·Hz1/2/W, respectively） at 5.3 Hz and 167.3 Hz, respectively. The thermal-time constant of the detector is 51ms, one magnitude lower than that of PZT ceramic detectors. The thermal isolation structure of the PZT thick film detector is beneficial to its high frequency response applications.