The direct epitaxial growth of III-V materials on Si substrates is one of the most promising methods to provide Si-based lasers for monolithic integration. Direct epitaxy of III-V on Si encounters three major challenges, which are large lattice mismatch, polarity difference, and thermal expansion mismatch, leading to threading dislocations, antiphase boundaries, and microthermal cracks, respectively. In this talk, I will show that, by homoepitaxial growth on a U-shaped patterned Si (001) substrate, highly uniform (111)-faceted Si sawtooth with underlying hollow structures can be formed. The (111)-faceted sawtooth structures can effectively annihilate the antiphase boundaries and terminate mostly the lattice mismatch induced dislocations at the III-V/Si interface, while the hollow structures can effectively reduce the thermal stress. The GaAs layers on (111)-faceted hollow Si (001) show a threading dislocation density of ~106/cm2 via the electron channeling contrast image method. The O-band emission of InAs/GaAs QDs on Si (001) shows similar intensity to that on the GaAs substrate. With such high quality III-V materials on Si, we demonstrate the high performance microcavity, microdisk and electrically pumped lasers both on Si and SOI substrates.
|