Abstract: There is an intense interest on integration of III-V materials on silicon and silicon-on-insulator for realisation of optical interconnects, optical networking, imaging and disposable photonics for medical applications. Advances in photonic materials, structures and technologies are the main ingredients of this pursuit. We investigate nano epitaxial lateral overgrowth (NELOG) of InP material from the nano openings on a seed layer on the silicon wafer, by hydride vapour phase epitaxy (HVPE). The grown layers were analysed by cathodoluminescence (CL) in situ a scanning electron microscope, time-resolved photoluminescence (TR-PL), and atomic force microscope (AFM). The quality of the layers depends on the growth parameters such as the V/III ratio, growth temperature, and layer thickness. CL measurements reveal that the dislocation density can be as low as 2 - 3·107 cm-2 for a layer thickness of ~6 μm. For comparison, the seed layer had a dislocation density of ~1·109 cm-2. Since the dislocation density estimated on theoretical grounds from TRPL measurements is of the same order of magnitude both for NELOG InP on Si and on InP substrate, the dislocation generation appears to be process related or coalescence related. Pertinent issues for improving the quality of the grown InP on silicon are avoiding damage in the openings due to plasma etching, pattern design to facilitate coalescence with minimum defects and choice of mask material compatible with InP to reduce thermal mismatch.
Abstract: We investigate nano-eptiaxial lateral overgrowth (NELOG) of InP from the nano-sized openings on a seed layer on the silicon wafer, by Hydride Vapor Phase Epitaxy (HVPE). The grown layers were analyzed by cathodoluminescence (CL) in situ a scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results from InP:S growth shows that the boundary plane of the grown layer has a major impact on the luminescence, indicating preferential orientation-dependent doping. Moreover, although there is clear evidence that most of the threading dislocations originating in the InP seed layer/Si interface are blocked by the mask, it appears that new dislocations are generated. Some of these dislocations are bounding planar defects such as stacking faults, possibly generated by unevenness in the mask. Finally, patterns where coalescence takes place at higher thickness seem to result in a rougher surface.
