SELECTIVE EPITAXIAL-GROWTH OF SIGE ALLOYS - INFLUENCE OF GROWTH-PARAMETERS ON FILM PROPERTIES

In this paper the selective growth of SiGe by low-pressure chemical vapor deposition is discussed on the basis of the present understanding of the selective growth process, with emphasis on the Si-Ge-Cl-H system and SiO2 masks. The selectivity of growth is a function of total pressure, temperature, Cl/H ratio and partial pressures of the reactive species. These factors, among others, influence strongly the chemistry of the deposition reaction. Their role must therefore be clearly understood, interpreted and predicted by thermochemical and kinetic analysis. An attempt will be made to determine the most significant parameters and to find selection criteria. The growth rate and composition dependence is affected by the pad size; this dependence is weaker at low-pressure than at atmospheric-pressure conditions. The evolution of relaxation by increasing the pad size is demonstrated for 16%Ge. finally, intense photoluminescence observed in dots 500 nm wide with multiple quantum wells is presented.