Crystallographic Imperfections in Epitaxially Grown Silicon

Abstract

Epitaxial Si layers grown on (111) Si substrates by vapor decomposition methods often exhibit a triangle and/or line type of surface defect. An investigation of such defects by optical microscopy and particularly transmission electron microscopy has shown the defects to be stacking faults. The stacking faults usually commence at certain points lying in or close to the substrate/layer interface, and develop in a regular manner along one or more of the three inclined {111} planes. As growth proceeds the stacking faults rapidly increase in area, spread laterally and eventually interact with one another. A simple growth mechanism is proposed based on the assumption that nucleation centers occasionally go down in incorrect sequence, i.e., small areas of stacking fault form on the (111) plane parallel to the substrate/layer interface. Many of the experimental observations can be explained using this model.