RHEED and XPS study of GaN on Si(111) grown by pulsed laser deposition

We have investigated growth mechanisms of GaN on Si (1 1 1) by pulsed laser deposition (PLD) using reflection high energy electron diffraction (RHEED) and X-ray photoelectron spectroscopy (XPS). We have found that the use of the AlN buffer layer dramatically improves the crystal quality of GaN. RHEE D observations have shown that the epitaxial growth of the buffer layer sta rts with a two-dimensional mode followed by island formation. XPS measureme nts have revealed that the AlN/Si hetero-interface has no SixNy interfacial layer. We have also found that the Si atoms in N sites are segregated at t he surface of tile AlN buffer layer. (C) 2001 Elsevier Science B.V. All rig hts reserved.