Tripyramid and Raised‐Triangle (111) Diamond‐Lattice Imperfections in Silicon Epitaxial Films

摘要

Two epitaxial defects, the raised triangle and the tripyramid, which appear in silicon and germanium films, are discussed with respect to their origin, crystallography, and electrical characteristics. These crystalline defects propagate from substrate surface contamination, such as refractory particles, and grow more rapidly than the defect‐free film. Referred to the substrate lattice, the raised‐triangle defect is bound by the inclined {111} planes; the defect lattice is rotated 180° around the [111] direction. The raised‐triangle defect provides the conditions necessary for the formation of the tripyramid structure. The three crystallite lattices of the tripyramid are rotated relative to the raised‐triangle lattice''s [111] direction such that their [1¯1¯1¯] directions are tilted 4° in the [211] direction. The major exposed faces of the tripyramid crystallites are {1¯1¯0} planes. Both the raised triangle and the tripyramid are centers for soft electrical junctions.