热释电非制冷红外焦平面探测器热绝缘结构

Thermal isolation structure for pyroelectric uncooled infrared focal plane array detector

热释电非制冷红外探测器由于具有可靠性高、成本低、无需制冷等优点,使其得到了广泛应用。在热释电探测器中,热绝缘结构具有红外热转换、机械支撑和热隔离等作用。良好的热绝缘结构是减小探测器热导率和改善其性能的关键。采用半导体光刻技术和牺牲层技术,在硅基底上制备了由牺牲层和Si3N4薄膜组成的微桥结构,该方法使探测器的微桥结构的制备与半导体工艺相兼容,并通过优化工艺参数,提高了微桥结构的机械强度,减小了热导,解决了制备热绝缘结构的关键技术,制备了像元中心距为50μm、填充因子为40%～60%、耐受温度≥500℃的320×240微桥列阵,该结构为制备高性能非制冷焦平面探测器奠定了基础。

Pyroelectric uncooled infrared detectors have been widely used owing to the excellent reliability, low cost and uncooling. The thermal isolation structure was adopted to accomplish infrared radiation conversion, machine support and thermal isolution. Therefore, good thermal isolation structure is the key issue for reducing the heat conductivity and improving the performance of uncooled IR detectors. The micro-bridge structure, which was made up of sacrifice layer and Si3N4 layer, was fabricated on the silicon substrate by the semiconductor photolithography and the sacrifice layer technique. The mechanical strength of micro-bridge structure was improved, and the heat conductivity was decreased by optimizing the processing parameters. Finally, the 320×240 micro-bridge structures with the pixel size of centre distance 50 μm, fill factor 40%-60% and bearing temperature more than 500 ℃ were successfully fabricated. It lays the foundation for the fabrication of the high performance uncooled infrared focal plane arrays.