Monolithic Ge/SiGe quantum well photodetectors integrated with SiN waveguides on 200 mm silicon wafers

Abstract The rapid growth of data processing is driving an urgent need for high-speed, low-power transceivers to support compute and interconnect demands. Here, we demonstrate a monolithically integrated O-band Ge/SiGe quantum-confined Stark effect (QCSE) photodetector seamlessly integrated with silicon nitride (SiN) waveguides on a silicon substrate. Our detector achieves 3-dB bandwidths more than 25 GHz under a moderate bias of − 5 V and demonstrates eye diagrams at 50 Gb s −1 in avalanche mode, with responsivities exceeding 4 AW −1 . Moreover, minimal dark current densities of 0.03 A cm −2 are measured under a − 3 V bias. By leveraging CMOS-compatible fabrication processes, we enable the integration of multiple quantum-well stacks with SiN for both modulation and detection, all within a single wafer-scale fabrication run on silicon. This work contributes to the development and convergence of electronics and photonics through fast low-power optical interconnect technologies, laying the foundation for future photonic integrated systems for both access and short-reach communication.