COMPARISON OF DIFFERENT DEPOSITION TECHNIQUES FOR EPITAXIAL COSI2 FILMS ON SI(111) BY HRTEM

Cobaltsilicide films were epitaxially grown on Si (111) by two different deposition techniques (pure metal evaporation and stoichiometric coevaporation of Co/Si) using a MBE chamber. These films, annealed at temperatures ranging from RT to 800-degrees-C, were investigated by TEM. The images were taken in cross sections [110] and with the electron beam perpendicular to the films, [111]. Above 400-degrees-C, codeposited samples show a complete reaction to CoSi2. In this case, no intermediate cobalt rich silicide phases (Co2Si, CoSi) were observed. In contrast to the evaporated pure metal film, pinhole free surfaces were obtained with the codeposition technique. The point to point resolution of the microscope does not reveal any visible differences in the image contrast of the interface CoSi2/Si up to 600-degrees-C for both deposition techniques.