III–V on Silicon Integrated Optical Devices

Silicon is widely regarded as the most significant material in semiconductor technology. It has been used as the primary material for CMOS transistors because of the excellent oxide-semiconductor interface that could be obtained by oxidizing the substrates. Since the commercialization of silicon-on-insulator (SOI) wafers, silicon has also been considered one of the best materials for photonics. The material itself is transparent to telecom wavelengths, and very compact optical waveguides could be realized from the large refractive index contrast between silicon and oxides. Although silicon has the potential to be used as a material for photonics purpose, it cannot emit light. To add light emitter on silicon, integration of III-V materials, which have direct bandgap structures, on silicon has been widely studied. Integration of III-V materials could solve one of the fundamental problems, i.e., light-emitting problem of silicon. This chapter provides an overview of research and development activities related to III-V/silicon integration. In the first half, the chapter explains current technical details regarding the integration methodologies of III-V/Si integration, and then the chapter reviews recent advancements of various heterogeneous integration technologies by each research institute.