GENERATION OF ATOMICALLY FLAT MGO(100) SURFACES - INFLUENCE OF AMBIENT GAS-COMPOSITION DURING HIGH-TEMPERATURE ANNEALS

Atomic force microscopy, reflection high energy electron diffraction ( RHEED), and x-ray photoelectron spectroscopy (XPS) have been used to f ollow the regeneration of atomically flat magnesium oxide (100) surfac es from samples initially etched in phosphoric acid. This regeneration process has been carried out by annealing samples at high temperature s in a range of gas compositions. The gas compositions investigated in clude argon, nitrogen, carbon dioxide, high partial pressures of water in nitrogen, and a range of partial pressures of oxygen; While acid e tching produces initially rough sui-faces, high temperature anneals (1 000 degrees C) are found to significantly reduce the surface roughness independent of gas composition. In contrast, only annealing circles i n the presence of oxygen (O-2) produced atomically flat stoichiometric MgO surfaces exhibiting good crystalline character, evidenced by dist inct square-shaped terraces with well-defined step edges, a 1X1 RHEED pattern, and a 1:1 ratio between magnesium and oxygen determined by XP S analysis. (C) 1998 American Vacuum Society. [S0734-2101(98);03806-8] .