Investigation of heteroepitaxy on nanoscopically roughened (001)Si by real-time spectroscopic polarimetry

We use a real-time spectroscopic polarimeter integrated with an organometallic chemical vapor deposition system to investigate growth of GaP on Si, and particularly nanoscopically roughened (nr-)Si. We find nanoroughening is necessary to increase the density of nucleation sites and decrease reactant mobility and thereby grow continuous films instead of widely spaced islands. The nrSi surfaces are more highly reactive to the trimethylgallium precursor than III-V growth surfaces, leading to the appearance of metallic Ga if standard growth conditions are used in the initial phase of heteroepitaxy.