MICROSTRUCTURAL STUDY OF VERY LOW RESISTIVITY TINX FILMS FORMED BY RAPID THERMAL LOW-PRESSURE METALORGANIC CHEMICAL VAPOR-DEPOSITION ONTO INP

Significant reductions in sheet resistivity of TiN(x) films formed by rapid thermal low-pressure metalorganic chemical vapour deposition onto InP, were realized by increasing the substrate temperature through the deposition, utilizing a post-deposition, in situ, heat treatment at temperatures up to 600-degrees-C, and adding tertiarybutylphosphine (TBP) metalorganic precursor to the reactive gas mixture. As a result, film resistivity values as low as 30 muOMEGA cm were obtained. Extensive transmission electron microscopy analysis was performed and the formation of a new and unidentified phase, having a similar crystal structure and lattice constant to those of Li9TiN2O2, was identified. This phase was formed as a result of TiN(x)-P intermixing during high-temperature post-deposition sintering of the TiN(x)/InP system, or as a result of incorporating P in the deposited TiN(x) film by bleeding TBP. This phase formation is likely to be the origin of the observed reduction in film resistivity.