硅基线性模式APD焦平面研制

针对三维激光雷达的应用场景对雪崩光电二极管(APD)焦平面的性能要求,研究并制备了一种2×128硅基线性模式APD焦平面组件,它由硅基APD焦平面阵列、读出电路和制冷封装管壳组成。APD像元采用拉通型结构,通过大尺寸微透镜实现了高填充因子,通过隔离环掺杂实现了串扰抑制。通过离子注入工艺实现了击穿电压和响应电流的均匀性。设计大带宽低噪声跨阻放大电路、高精度计时电路,实现了窄脉宽、高灵敏度探测。采用气密性封装,实现了APD焦平面制冷一体化封装,制冷温差在40 K以上。测试结果表明,焦平面的探测阈值光功率可达3.24 nW,响应非均匀性为3.8%,串扰为0.14%,最小时间分辨率可达0.25 ns,实现了强度信息与时间信息同时输出的功能。

Fabrication of Silicon Linear-mode APD Focal Plane Arrays

Aiming at the requirements of avalanche photodiode (APD) focal plane in 3D-lidar imaging, a 2×128 silicon linear-mode APD focal plane module was prepared. It consisted of silicon based APD focal plane array, readout circuit and refrigeration package shell. APD pixels adopted the reach-through structure, achieved a high fill factor by large size micro-lens arrays, realized crosstalk suppression through isolation ring doping, and achieved breakdown voltage and response current uniformity through optimization of the ion implantation process. A low noise transimpedance amplifier circuit with large bandwidth and a high precision timing circuit were designed to realize narrow pulse width and high sensitivity detection. Airtight encapsulation was performed to achieve integrated APD focal plane refrigeration encapsulation with a refrigeration temperature difference over 40K. The test results show that the detection threshold optical power of the focal plane can reach 3.24nW, and the response non-uniformity is 3.8%, the crosstalk is 0.14%, and the minimum time resolution can reach 0.25ns, realizing the simultaneous output function of intensity information and time information.