Maskless epitaxial lateral overgrowth of GaN layers on structured Si(111) substrates

GaN layers are laterally overgrown by metalorganic chemical vapor depositio n on structured Si(111) substrates in a single growth process. The substrat es are structured with parallel grooves along the Si <1-10 > or perpendicul ar to the Si <1-10 > direction by standard photolithography and subsequent dry etching. Due to the anisotropic chemical dry etch process, the remainin g Si ridges are underetched. The GaN layer grows nearly exclusively on the bottom of the grooves and on the top of the ridges between the grooves. The se two growth fronts are completely separated from each other. As a consequ ence, the GaN layer growing from the ridge area between grooves can extend over the grooves. This process is similar to the so called pendeo-epitaxy p rocess, but is completely mask free during growth and does not require any growth interruption. The improvement of the crystalline and the optical qua lity of the GaN layer is demonstrated by atomic force microscopy and cathod oluminescence spectroscopy. (C) 2001 American Institute of Physics.