Germanium-on-silicon (Ge-on-Si) avalanche photodiodes (APDs) are widely used in near-infrared detection, laser ranging, free space communication, quantum communication, and other fields. However, the existence of lattice defects at the Ge/Si interface causes a high dark current in the Ge-on-Si APD, degrading the device sensitivity and also increasing energy consumption in integrated circuits. In this work, we propose a novel surface illuminated Ge-on-Si APD architecture with three terminals. Besides two electrodes on Si substrates, a third electrode is designed for Ge to regulate the control current and bandwidth, achieving multiple outputs of a single device and reducing the dark current of the device. When the voltage on Ge is −27.5 V$-27.5\mathrm{V}$, the proposed device achieves a dark current of 100 nA, responsivity of 9.97 A/W at −40 dBm$-40\mathrm{dBm}$ input laser power at 1550 nm, and optimal bandwidth of 142 MHz. The low dark current and improved responsivity can meet the requirements of autonomous driving and other applications demanding weak light detection.

中文翻译：

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用于减少暗电流的具有扩展 p 电荷层的三端硅上锗雪崩光电二极管

硅上锗（Ge-on-Si）雪崩光电二极管（APD）广泛应用于近红外探测、激光测距、自由空间通信、量子通信等领域。然而，Ge/Si 界面处晶格缺陷的存在导致 Ge-on-Si APD 中的暗电流很高，降低了器件的灵敏度，也增加了集成电路的能耗。在这项工作中，我们提出了一种具有三个端子的新型表面照明 Ge-on-Si APD 架构。除了Si衬底上的两个电极外，还为Ge设计了第三个电极来调节控制电流和带宽，实现单个器件的多路输出，降低器件的暗电流。当 Ge 上的电压为− 27.5 V $-27.5\mathrm{V}$，所提出的器件实现了 100 nA 的暗电流，在- 40 dBm $-40\mathrm{dBm}$的 1550 nm 输入激光功率下的响应度为 9.97 A/W，最佳带宽为 142 MHz。低暗电流和改进的响应度可以满足自动驾驶和其他需要弱光检测的应用的要求。