Extended Wavelength Responsivity of a Germanium Photodetector Integrated With a Silicon Waveguide Exploiting the Indirect Transition
Extended Wavelength Responsivity of a Germanium Photodetector Integrated With a Silicon Waveguide Exploiting the Indirect Transition
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DOI：
10.1109/jstqe.2019.2938057
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发表时间：
2020-03
影响因子：
4.9
通讯作者：
R. Anthony;D. Hagan;Dylan Genuth-Okon;L. Martinez Maestro;I. Crowe;M. Halsall;A. Knights
中科院分区：
文献类型：
--
作者：
R. Anthony;D. Hagan;Dylan Genuth-Okon;L. Martinez Maestro;I. Crowe;M. Halsall;A. Knights
描述了使用生长在硅波导上的渐逝耦合锗探测器在1850至2000 nm波长范围内的光探测。使用与0、C和L波段中的操作相关联的工艺流程在硅光子铸造厂制造器件，并且因此提供了易于获得的用于扩展波长检测的解决方案。本征灵敏度是通过间接的能带跃迁，这是增强拉伸应变，我们假设，它可能会进一步增强所产生的缺陷与Ge在Si上生长的热过程。p-i-n探测器的响应度在1850 nm处为20 mA/W，在2000 nm处下降到5 mA/W，探测器长度为50 μm。通过锗检测器中的电掺杂来抑制响应度，所述锗检测器提供来自自由载流子的寄生吸收。建议对当前设计进行修改，使得直接生长在硅波导上的集成锗p-i-n检测器将适合于高达至少2000 nm波长的高带宽光检测。利用同样的间接跃迁制作了分离吸收电荷倍增雪崩光电探测器。该探测器在1850 nm和1970 nm处的响应度分别为0.31 A/W和0.08 A/W，探测器长度仅为14 μm。
Photo-detection in the wavelength range 1850 to 2000 nm using evanescently-coupled germanium detectors grown on silicon waveguides is described. Devices were fabricated at a silicon photonics foundry using a process flow associated with operation in the O, C and L bands, and as such offer a solution for extended wavelength detection which is readily available. Intrinsic sensitivity is via indirect band transitions, which is enhanced by tensile strain and we postulate that it may be further enhanced by defects which arise from the thermal processes associated with Ge on Si growth. The responsivity of p-i-n detectors is 20 mA/W at 1850 nm falling to 5 mA/W at 2000 nm, for a detector length of 50 μm. Responsivity is suppressed by electrical doping in the germanium detector which provides parasitic absorption from free carriers. Modifications to the current design are suggested such that integrated germanium p-i-n detectors, directly grown on silicon waveguides would be suitable for high-bandwidth photo-detection up to at least a wavelength of 2000 nm. A Separate-Absorption-Charge-Multiplication Avalanche Photo-Detector is fabricated exploiting the same indirect transition. This detector has a responsivity of 0.31 A/W at 1850 nm and 0.08 A/W at 1970 nm, for a detector length of only 14 μm.