  Silicon photonics is a rapidly developing technology that promises to
revolutionize the way we communicate, compute, and sense the world. However,
the lack of highly scalable, native CMOS-integrated light sources is one of the
main factors hampering its widespread adoption. Despite significant progress in
hybrid and heterogeneous integration of III-V light sources on silicon,
monolithic integration by direct epitaxial growth of III-V materials remains
the pinnacle in realizing cost-effective on-chip light sources. Here, we report
the first electrically driven GaAs-based multi-quantum-well laser diodes fully
fabricated on 300 mm Si wafers in a CMOS pilot manufacturing line. GaAs
nano-ridge waveguides with embedded p-i-n diodes, InGaAs quantum wells and
InGaP passivation layers are grown with high quality at wafer scale, leveraging
selective-area epitaxy with aspect-ratio trapping. After III-V facet patterning
and standard CMOS contact metallization, room-temperature continuous-wave
lasing is demonstrated at wavelengths around 1020 nm in more than three hundred
devices across a wafer, with threshold currents as low as 5 mA, output powers
beyond 1 mW, laser linewidths down to 46 MHz, and laser operation up to 55
{\deg}C. These results illustrate the potential of the III-V/Si nano-ridge
engineering concept for the monolithic integration of laser diodes in a Si
photonics platform, enabling future cost-sensitive high-volume applications in
optical sensing, interconnects and beyond.
