Growth process of CuO(111) and Cu2O(001) thin films on MgO(001) substrate under metal-mode condition by reactive dc-magnetron sputtering

The growth process of CuO and CU2O thin films on MgO(0 0 1) substrates by reactive dc-magnetron sputtering was studied by reflection high-energy electron diffraction (RHEED) and atomic-force microscopy (AFM). The RHEED pattern and AFM image showed that (1) three-dimensional Cu(0 0 1) islands grew on MgO under the nonreactive sputtering condition, (2) CuO(1 1 1) was deposited layer by layer on MgO at 400 degrees C under the reactive sputtering condition, and (3) the film deposited at 600 degrees C in the initial growth stage was composed of three-dimensional Cu islands because O-2 gas could not be incorporated into them due to the low sticking coefficient of 02 on MgO under the reactive sputtering condition. The layer-by-layer CuO(1 1 1) thin-film growth process is discussed from the viewpoint that Cu and oxygen species are supplied in stoichiometry onto the MgO substrate to form CuO thin-film crystals while maintaining minimum interfacial energy between CuO and MgO. (c) 2007 Elsevier Ltd. All rights reserved.