【作者】 王志伟；

【导师】 孙芳魁；

【作者基本信息】 哈尔滨工业大学 ， 光学， 2014， 硕士

【摘要】 微元阵Si-APD以其高增益、响应速度快、灵敏度高、动态范围大、对磁场不敏感等优点而成为近年来单光子探测器的研究热点。而其暗电流一直是制约其微弱光探测精度的主要因素，这限制了它在军事、医疗、生物、通信等众多研究领域的应用。本论文从纵向结构的掺杂分布和横向结构的串扰两方面对影响微元阵Si-APD的暗电流的因素进行了探讨。纵向结构上，首先，构建各层均匀掺杂的微元Si-APD的结构模型，以电场分布、离化率和电场关系、倍增因子、暗电流的研究思路构建了理论分析框架，为暗电流的研究提供了方法。其次，通过蒙特卡洛模拟方法对离化率与电场关系进行研究。然后，通过优化微元Si-APD(对1064nm)得到典型暗电流14.5nA、击穿电压100.7V的最优掺杂分布。由此得出结论，暗电流主要为产生复合电流。通过降低场控层浓度能有效降低暗电流，但过低的场控层浓度会失去调节电场分布的作用，而导致击穿电压过大。最后，通过Silvaco仿真结构特性，得到102.2V的击穿电压以及低达2.5nA的暗电流。仿真表明，加合适的钝化层和增透膜可以使暗电流降低和灵敏度提高。对比得出，仿真和实验结果较吻合。横向结构上，本论文通过加氧化层和Al层覆盖的沟道，有效降低了相邻微元Si-APD间的光串扰和电串扰的影响。更多还原

【Abstract】 Micro-pixel array Si-APD, with its advantage of high gain, fast response, highsensitivity, wide dynamic range, not sensitive to magnetic fields, etc, has beenresearch focus of single-photon detectors in recent years. But dark current is always amajor factor restricting the detection accuracy of feeble light, which limits itsapplication in many research fields, such as military, medical, biological,communications and so on.We discuss the factors affecting dark current from two factors, the doping profileof the vertical structure and the crosstalk of the horizontal structure.On the vertical structure, firstly, we construct theory structure model of micro-pixelSi-APD with uniform doping in each layer. Then, with the research thought of electricfield distribution, relationship between electric field and ionization rate, multiplicationfactor and dark current，we build a theoretical analysis framework，which provides amethod for dark current research. Secondly, we study the relationship between electricfield and ionization rate with monte carlo simulation method. Then, the micro-pixelSi-APD is optimized (for1064nm) to have an optimal doping distribution which has atypical dark current of14.5nA and a breakdown voltage of100.7V. this come to theconclusion that dark current is mainly generation-recombination current. By reducingthe concentration of field control layer, we can effectively reduce dark current, but toolow concentration will lose the function of adjusting electric field distribution, and willlead to the breakdown voltage too large. Finally, simulating with silvaco, we gain a lowtypical dark current of2.5nA and a low breakdown voltage of100.7V. Simulationshows that suitable passivation layer and coating can reduce dark current and increasesensitivity. with contrast, the simulation and experimental results fit well.On the horizontal structure，this paper effectively reduces light crosstalk andelectrical crosstalk effects between two adjacent micro-pixel Si-APDs through channelwhich sequentially covered with oxide layer andAl layer.更多还原