10. CMOS-Compatible Laser
Category: Silicon Photonics
Paper 2.6 - Direct Bandgap GeSn Microdisk Lasers at 2.5 µm for Monolithic Integration on Si-Platform; Stephan Wirths et al, Forschungszentrum Jülich/ Paul Scherrer Institute/ETH/University of Leeds/University of Grenoble/CEA LETI Minatec
Silicon photonics is an evolving technology in which light, not wires, carries data within and among computer chips. Light can carry more data, faster, using less power than metal wires. Silicon is ubiquitous in electronics but it is a poor material for light-emitters like lasers, and the integration of lasers made from other materials into standard silicon CMOS devices is problematic. But if that could be done more easily, then much more powerful computers and other digital systems could be built. A research team from several European research organizations and universities, led by Germany’s Forschungszentrum Jülich institute, will report on a silicon-based direct-bandgap germanium-tin (GeSn) micro-disk laser that emits at a lasing wavelength of 2.5 μm at a power output of 221 kW/cm2. The device was built using standard CMOS-compatible processing and was monolithically integrated on a silicon platform. Its 560-nm-thick GeSn epitaxial layers were grown on Ge buffers/Si substrates. Its lasing performance arises from 1) straining the epitaxial layers so they become direct bandgap materials; and 2) its micro-disk cavity architecture. The work is an important step toward integrated silicon photonics.