Zhang Qiang, Yu Hui, Qi Tian, Fu Zhilei, Jiang Xiaoqing, Yang Jianyi
College of Information Science and Electronics Engineering, Zhejiang University, Hangzhou, 310027, China.
Sci Rep. 2018 Jul 2;8(1):9929. doi: 10.1038/s41598-018-28139-w.
Silicon waveguide photodiodes (SiWG PD) based on the bulk defect-mediated absorption (BDA) of sub-bandgap photons are suitable to realize in-line optical power monitors for silicon photonic integrated circuits. Deep-level states to enable the BDA can be induced by exploiting the ion implantation steps that are used to embed PN junctions for carrier-depletion-based modulators. This manner usually exhibits limited responsivities since relevant processing conditions are optimized for the modulation rather than the BDA. In this letter, we solve this issue with the doping compensation technique. This technique overlaps P-type and N-type implantation windows at the waveguide core. The responsivity is enhanced due to the increased density of lattice defects and the reduced density of free carriers in the compensated silicon. Influences of the dimension of the dopant compensation region on responsivity and operation speed are investigated. As the width of this region increases from 0 μm to 0.4 μm, the responsivity at -5 V is improved from 2 mA/W to 17.5 mA/W. This level is comparable to BDA based SiWG PDs relying on dedicated ion bombardments. On the other hand, a bit-error-rate test at 10 Gb/s suggests that the device with 0.2-μm-wide compensation region exhibits the highest sensitivity.
基于体缺陷介导的亚带隙光子吸收（BDA）的硅波导光电二极管（SiWG PD）适用于实现硅光子集成电路的在线光功率监测器。用于基于载流子耗尽的调制器的PN结嵌入的离子注入步骤可诱导出实现BDA所需的深能级状态。由于相关的处理条件是针对调制而非BDA进行优化的，所以这种方式通常表现出有限的响应度。在本文中，我们用掺杂补偿技术解决了这个问题。该技术使P型和N型注入窗口在波导芯处重叠。由于补偿硅中晶格缺陷密度的增加和自由载流子密度的降低，响应度得到了提高。研究了掺杂补偿区域尺寸对响应度和工作速度的影响。当该区域的宽度从0μm增加到0.4μm时，-5V下的响应度从2mA/W提高到了17.5mA/W。这个水平与依赖于专门离子轰击的基于BDA的SiWG PD相当。另一方面，在10Gb/s下的误码率测试表明，具有0.2μm宽补偿区域的器件表现出最高的灵敏度。
