  Graphene-based devices have shown great promise for several applications. For
graphene devices to be used in real-world systems, it is necessary to
demonstrate competitive device performance, repeatability of results,
reliability, and a path to large-scale manufacturing with high yield at low
cost. Here, we select single-layer graphene electro-absorption modulators as
test vehicle and establish their wafer-scale integration in a 300mm pilot CMOS
foundry environment. A hardmask is used to shape graphene, while tungsten-based
contacts are fabricated using the damascene approach to enable CMOS-compatible
fabrication. By analyzing data from hundreds of devices per wafer, the impact
of specific processing steps on the performance could be identified and
optimized. After optimization, modulation depth of 50 $\pm$ 4 dB/mm is
demonstrated on 400 devices measured using 6 V peak-to-peak voltage. The
electro-optical bandwidth is up to 15.1 $\pm$ 1 1.8 GHz for 25$\mu$m-long
devices. The results achieved are comparable to lab-based record-setting
graphene devices of similar design and CVD graphene quality. By demonstrating
the reproducibility of the results across hundreds of devices, this work
resolves the bottleneck of graphene wafer-scale integration. Furthermore,
CMOS-compatible processing enables co-integration of graphene-based devices
with other photonics and electronics building blocks on the same chip, and for
high-volume low-cost manufacturing.
