| Research Abstract |
For the deposition of malti-component films by MOCVD, the film composition is generally difficult to control. This is because the evaporation rate of each MO reagent is not constant during the film deposition. On the other hand, if mixed MO reagents were completely vaporized in an evaporation vessel, the composition of the vapors would be constant. In the present study, this idea was applied to MOCVD for (Ni, Zn)Fe_2O_4, (Ni, Zn, Cu)Fe_2O_4, PbTiO_3(PT), Pb(Ti, Zr)O_3(PZT), ZnO : Cu, In, and ITO (In_2O_3 : SnO_2) thin films. For the preparation of (Ni, Zn)Fe_2O_4 thin films, Fe(acac)_2, Zn(acac)_2 and Ni(acac)_2 were mixed with a composition of Ni : Zn : Fe=1.0 : 1.6 : 2.6-1.0 : 1, 6 : 10.4 and were then completely vaporized at 210℃ in the evaporation vessel. The mixed vapor reacted with oxygen to deposit on an α-A1_2O_3 substrate. The deposition conditions were ; flow rate of oxygen : 100 seem, substrate temperature : 500-700℃, deposition time : 20 min. The reproducibUity was establis
… More
hed on the relationship between film composition and the composition of CVD reagents. Thickness of the film was about 1.3-3.1μm. The magnetic properties of the Nio_<40>Zn_<0.60>Fe_2O_4 thin film at 25℃ were measured as 81emu/g (as deposited at 600℃) and 83emu/g (annealed at 1000℃ for 4h in air). Furthermore, (Ni, Zn, Cu)Fe_2O_4 thin films have been deposited by the use of Fe(acac)_3, Zn(acac)_2, Ni(acac)_2 and Cu(acac)_2.The magnetic properties were improved by CuO doping.
The PT film with stoichiometric composition of PbTiOs was obtained, using our apparatus. For the PZT films, single phase of perovskite was obtained, but the content of zirconium was less than that in the stoichiometric one. This method was also useful for the doping. ZnO'Cu or In films and ITO thin films were respectively deposited with the reproducibility of electrical conductivities. As the result, the simple apparatus without the use of carrier gas was constructed. In addition, the reproducibility was established on the relationship between mixing ratio of raw materials and the film composition. MO reagents were efficiently deposited in this method. Less
|
