MOCVD of MgAl2O4 thin ®lms using new single molecular precursors: application of b-hydrogen elimination to the growth of heterometallic oxide ®lms

We have deposited the MgAl2O4 thin ®lms on Si(1 0 0) substrates in the temperature range of 270 6008C using newly developed single molecular precursors of Mg[(m-OtBu)2AlMe2]2 and Mg[Al(OtBu)4]2 by MOCVD. Polycrystalline, crack-free stoichiometric MgAl2O4 thin ®lms were successfully grown on at as low as 4008C. This growth temperature was much lower than that of conventional CVD, and this is the ®rst report of the MgAl2O4 growth using Mg[(m-OtBu)2AlMe2]2. During ®lm deposition, the vapor pressure of Mg[Al(OtBu)4]2 was decreased due to oligomerization of the precursor itself. When Mg[(m- OtBu)2AlMe2]2 was used, however, the vapor transport problem of the precursor was solved by introducing more volatile alkyl group. b-Hydrogen elimination was employed in the growth mechanism. The synthesized precursors and the as-grown ®lms were characterized with NMR, XRD, XPS, RBS, and SEM, and the gas-phase by-products of the CVD reaction were collected and identi®ed by gas chromatography. # 2001 Elsevier Science B.V. All rights reserved.