Studies of High Quality InP Layrs Heteroepitaxially Grown on Si Substrates by Epitaxial Lateral Overgrowth and Fabrication of Long-wavelengh Laser Diodes

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Growth of III-V materials on Si substrates is a key technology for fabricating opto-electronic integrated circuits (OEICs). Though a lot of studies about the growth of III-V materials on Si have been carried out, a large lattice mismatch and a big difference in the thermal expansion coefficient between III-V materials and Si substrates still bring high dislocation density (-10^6 cm^<-2>) and strong residual stress in the layrs. The dislocations in the III-V materials strongly deteriorate the device characteristics and their lives, therefore, further crystallinity improvement is necessary to obtain devices with high performance and excellent reliability.Epitaxial lateral overgrowth (ELO) which is a new technique to grow thin layrs laterally through an opening in SiO_2 film, which is called as "a line seed", is a very promising technique to overcome these difficulties. In ELO,propagation of dislocations is stopped by the SiO_2 mask and dislocation-free areas are obtained on the laterally overgrown regions.In order to grow dislocation-free InP layrs on Si substrates, ELO technique was used and a long-wavelength laserdiode structure was fabricated on it.Spatially resolved photoluminescence measurements showed that the optical quality of the ELO layrs was almost the same as that of a homoepitaxially grown InP layr. The ELO technique is not only useful to obtain dislocation-free regions but also useful to release residual stress. The growth mechanism of ELO was also studied in terms of the surface supersaturation. The optimized growth condition brought wide dislocation-free InP layrs on Si substrates with high reproducibility. The long-wavelength laserdiode structure fabricated on the ELO layr showed excellent optical quality, which suggests the realization of the laser with high performances. 3-dimensional finite element method calculation showed that the island structures of ELO layrs were useful to reduce the residual stress.