Design and study of photon-assisted heteroepitaxial growth system

Development of heterogeneous integration for optoelectronic and sensor applications is discussed. Improvement of the quality of high mismatch layers obtained is the final objective of the research. The study and design of an experimental set up that permits the growth of compound semiconductors is presented. Low pressure photo-assisted metallorganical vapor phase epitaxy is chosen. The system is equipped with an in situ probe of the epitaxial growth process based on the detection of any intensity modulation of the photoemission current near threshold. The interest in photons for stimulation of the epitaxial process is due to the amount of work done in this field. It is shown that the layers obtained during photonic irradiation could be improved by an activated mechanism of nonradiative recombination of the photogenerated carrier. Interpretation of the photoemission signal and particularly the physical origin of the observed oscillations during growth of GaAs by MBE is studied. It is assumed that the photoemission properties depend on the chemical nature of the absorbed atoms and on their local configurations. In this way, a theoretical model is developed that associates a simple growth model with atomic photoemission models. The results obtained exhibit the same features observed experimentally and seem to be strongly dependent on the As2 and Ga molecular and atomic adsorption mechanisms, on the roughness of the growing layer and on the growth mode (two or three dimensions).