A study of the chemical vapor deposition of novel gallium indium phosphide structures for optoelectronic applications

Future generations of microchips will be required to meet demands for increased data transmission rates as well as reduced power consumption. Current technology dictates that this improvement in computational capacity come from adding more metal line interconnects in parallel. However, the resistance, capacitance, and inductance associated with these lines will limit chip performance. One solution to this problem is the use of an optical databus for off-chip communications. Although various methods employing hybrid techniques have been used successfully, it would be more desirable to use a technology that could be applied to all of the devices on a chip simultaneously. The epitaxial growth of direct bandgap materials on silicon substrates is one such technique.; This work suggests a method by which direct bandgap Ga_xIn _1−xP Stranski-Krastanov islands may be deposited on silicon substrates by metal organic chemical vapor deposition (MOCVD). The deposition of Ga _xIn_1−xP islands on GaP substrates was investigated, and it was found that good quality, light-emitting material could be grown with an emission wavelength of 630 nm. In addition, it was found that GaP could be grown on silicon by selective area epitaxy. By combining these two technologies, optical material could be successfully deposited on silicon.; Additional research focused on techniques to improve the quality of the luminescence from the Ga_xIn_1−xP islands and to test the potential of this material system in device structures. Both the wavelength and intensity of the photoluminescence (PL) emission from the islands were strongly dependant on growth parameters such as growth temperature, trimethylindium (TMI) flow fraction, and cap layer thickness. Changing these conditions during growth influenced the diffusion and segregation of In to the islands, the hydrostatic strain in the layer, and the degree of ordering in the Ga _xIn_1−xP islands. Optically pumped device structures were damaged by the UV probe beam, making the results of this type of testing inconclusive. Electrically pumped devices saturated at fairly low current densities, and lasing was not observed in any of the structures. Methods to increase the amount of material in the active region and the emission intensity are still in the investigative stages.