IRON-OXIDE FILMS WITH SPINEL, CORUNDUM AND BIXBITE STRUCTURE PREPAREDBY PLASMA-ENHANCED METALORGANIC CHEMICAL-VAPOR-DEPOSITION

Iron oxide films of spinel, corundum and bixbite structure were prepar ed on glass substrates at 150-450 degrees C by plasma-enhanced metalor ganic chemical vapor deposition and the formation diagram was determin ed by X-ray diffraction and conversion electron Mossbauer spectroscopy measurements. Spinel-type Fe3O4+delta films were formed in the low O- 2 flow rate range of 10-25 cm(3) min(-1) and the films deposited at 30 0 degrees C or above possessed the (100) preferred orientation. For hi gh O-2 flow rate in the range of 30-45 cm(3) min(-1), corundum-type al pha-Fe2O3 films were formed at high substrate temperatures of 350-450 degrees C and bixbite-type beta-Fe2O3 films were formed at low substra te temperatures of 200-400 degrees C. (100) oriented NaC1-type FeO coe xisting with the Fe(3)Q(4+delta) films were infrequently formed under deposition conditions for (100) oriented Fe3O4+delta films. The follow ing two step growth model of preferentially (100) oriented Fe3O4+delta films is proposed: (1) formation of a (100) oriented FeO film, (2) tr ansformation of the FeO film into (100) oriented Fe3O4+delta films by means of plasma oxidation during deposition. The deposition rate of th e films increased with increasing RF power.