High-Responsivity Low-Voltage 28-Gb/s Ge p-i-n Photodetector With Silicon Contacts

Abstract

Abstract-We report a high-performance germanium waveguide photodetectors (WPDs) without doping in germanium or direct metal contacts on germanium, grown on and contacted through a silicon p-i-n diode structure. Wafer-scale measurements demonstrate high responsivities larger than 1.0 A/W across the C-band and low dark current of ∼3 nA at -1 V and ∼8 nA at -2 V. Owing to its small dimensions, the Ge WPD exhibits a high optoelectrical 3-dB bandwidth of 20 and 27 GHz at low-bias voltages of -1 and -2 V, respectively, which are sufficient for operation at 28 Gb/s. The reduced processing complexity at the tungsten contact plug module combined with the high responsivity makes these Ge WPD devices particularly attractive for emerging low-cost CMOS-Si photonics transceivers Index Terms-Germanium photodetector, optical interconnects, silicon photonics.

Carrier lifetime assessment in integrated Ge waveguide devices

“…INTRODUCTION ilicon photonics is widely considered solution in solving the bandwidth bottleneck of electrical interconnects for systems [1]. Ge waveguides (WG) with an diode integrated on a silicon photonics platf be used as a building block for a number of de photodetectors [2], Ge electro-absorption m well as Ge variable optical attenuators (VOA (with high n-type doping and tensile strain [4]). In this work, we extract carrier waveguides grown on Si, using time-re transmission pump-probe spectroscopy.…”

III-V-on-Silicon Photonic Devices for Optical Communication and Sensing

“…For the telecommunication wavelength range, Ge-based photodetectors are typically used. Recently, low dark current, high responsivity devices have been demonstrated with a cut off wavelength of about 1600 nm [76]. In many spectroscopic sensing applications one wants to work beyond a wavelength of 1600 nm, because of the more pronounced absorption features at longer wavelengths.…”

100-Gbps RZ Data Reception in 67-GHz Si-Contacted Germanium Waveguide p-i-n Photodetectors

“…We demonstrated a Ge p-i-n photodetector without metal contacts on Ge, grown on and contacted through a silicon p-i-n diode structure, adopting a 400 nm thick Ge layer (referred to as Si-LPIN GePD hereafter) [11]. The opto-electrical 3-dB bandwidth was transit-time limited to 20 GHz at -1 V bias at 1550 nm.…”