STRAIN COMPENSATION BY GE IN B-DOPED SILICON EPITAXIAL-FILMS

A compensation of stress induced in silicon epitaxial films heavily doped with boron was investigated. Addition of a controlled amount of germanium during the film growth allows one to attain a desired compressive or tensile stress in the film, or its complete elimination. The data shows very good correlation with a theoretical model adapted from Herzog et al. [J. Electrochem. Soc. 131, 2969 (1984)]. A 6.45 : 1 ratio of atomic concentrations of Ge and B completely eliminates stress in these films. We determined a critical amount of strain in the films, congruent-to 2-4 mum thick, beyond which misfit dislocations are generated.