EFFECTS OF THE PURITY OF METALORGANIC SOURCES ON THE ELECTRICAL PROPERTIES OF Pb(Zr,Ti)O_3 THIN FILMS BY MOCVD

摘要

Effects of the purity of metalorganic Pb, Zr and Ti precursors (Pb(C_2H_5)_4, Zr(O-tC_4H_9)_4 and Ti(O-iC_3H_7)_4) on the electrical properties of Pb(Zr,Ti)O_3 (PZT) thin films prepared by MOCVD were investigated. Generally, PZT thin films prepared using the high purity Pb source precursor had a tendency to show better current densities, breakdown electric fields and switching fatigue characteristics than those of PZT films prepared using the low purity precursor. On the other hand, distinct purity effects of Zr and Ti source precursors were not observed. These experimental results suggest that some types of impurities play important roles as donors and acceptors and influence ionic movement and space charge. At this stage, it is not well understood which impurities contained in precursors play important roles and what is the difference in the impurity effects between Pb, and Zr and Ti precursors.