Ultra-fast germanium photodiode with 3-dB bandwidth of 265 GHz

作者：Stefan Lischke, Anna Pęczek, Jesse Morgan, Keye Sun, Daniel Steckler, Y. Yamamoto, F. Korndörfer, Christian Mai, S. Marschmeyer, Mirko Fraschke, Andreas Krüger, Andréas Beling, Lars Zimmermann · 发表于：Nature Photonics · 年份：2021 · DOI：10.1038/s41566-021-00893-w · 被引用次数：347 · 研究领域：Photonic and Optical Devices、Advanced Photonic Communication Systems、Advanced Fiber Laser Technologies

Abstract On a scalable silicon technology platform, we demonstrate photodetectors matching or even surpassing state-of-the-art III–V devices. As key components in high-speed optoelectronics, photodetectors with bandwidths greater than 100 GHz have been a topic of intense research for several decades. Solely InP-based detectors could satisfy the highest performance specifications. Devices based on other materials, such as germanium-on-silicon devices, used to lag behind in speed, but enabled complex photonic integrated circuits and co-integration with silicon electronics. Here we demonstrate waveguide-coupled germanium photodiodes with optoelectrical 3-dB bandwidths of 265 GHz and 240 GHz at a photocurrent of 1 mA. This outstanding performance is achieved by a novel device concept in which a germanium fin is sandwiched between complementary in situ-doped silicon layers. Our photodetectors show internal responsivities of 0.3 A W −1 (265 GHz) and 0.45 A W −1 (240 GHz) at a wavelength of 1,550 nm. The internal bandwidth–efficiency product of the latter device is 86 GHz. Low dark currents of 100–200 nA are obtained from these ultra-fast photodetectors.