CRITICAL THICKNESS FOR GROWTH OF EPITAXIAL GRAINS IN SILICON FILM DEPOSITED ON SUPERLATTICE SURFACE OF SILICON (111)

When Si film is grown on the 7 x 7 surface of Si(111) held at temperatures (T(S)) below 300-degrees-C, some epitaxial grains grow in the film deposited at thicknesses (d) below a certain value, d(C). The value of d(C) depends on T(S) and the growth rate of the film. This could be explained qualitatively by the nucleation process of two-dimensional crystalline nuclei on the growing surface which becomes rough with approaching d(C). Some consideration is also given to the film which is initially in an amorphous state, and is rearranged to crystallize during the film growth.