Monolithic integration of III-V optical interconnects on Si using SiGe virtual substrates

Working optical links epitaxially grown by atmospheric MOCVD and fabricated on Si via SiGe virtual substrates are demonstrated for the first time. The SiGe virtual substrates are graded from Si substrates to 100% Ge. Because of the 0.07% lattice mismatch between GaAs and Ge, high-quality GaAs-based thin films with threading dislocation densities <3×10⁶ cm^–2 were realized. The optical link consists of a GaAs PIN-LED and a GaAs PIN detector diode. A vertical-coupling scheme was utilized to couple devices with a Al_0.15Ga_0.85As waveguide. Waveguides of varying length, Y-junctions, and bends were fabricated. The straight waveguides exhibited loss of approximately 144 dB cm^–1.An erratum to this article can be found at