AUTOSTOICHIOMETRIC VAPOR-DEPOSITION OF FERROELECTRICS - THE STOICHIOMETRY OF CO-EVAPORATIONS

The stoichiometry control in MOCVD of multicomponent oxide ferroelectr ics is studied by a comprehensive approach. Experimental results on th e stoichiometry of chemically controlled co-evaporation are reported. The temperature dependence of the vapor pressures for single alkoxides Ta(O CnH2n+1)(5) and Nb(O CnH2n+1)(5) are compared with those of doub le alkoxides LiTa(O CnH2n+1)(6) and LiNb(OCnH2n+1)(6). The stoichiomet ry of evaporation processes for the double alkoxides under various con ditions is studied by controlled sublimation along with the compositio n analysis of both the sublimate and the residue. It is found that the stoichiometry of co-evaporation depends on the relative partial press ure of the single alkoxides at the respective evaporation temperature.