Comparison of Pb(Zr, Ti)O_3 capacitors sandwiched with conductive La_(0.5)Sr_(0.5)CoO_3 and non-conductive Bi_(3.25)La_(0.75)Ti_3O_(12) layers

摘要

Ferroelectric capacitors of Bi_(3.25)La_(0.75)Ti_3O_(12)/PbZr_(0.4)Ti_(0.6)O_3/Bi_(3.25)La_(0.75)Ti_3O_(12) (BLT/PZT/BLT) and La_(0.5)Sr_(0.5)CoO_3/PbZr_(0.4)Ti_(0.6)O_3/La_(0.5)Sr_(0.5) CoO_3 (LSCO/PZT/LSCO) are fabricated, respectively, on Si substrates in order to study the properties of PZT film sandwiched by conductive oxide and non-conductive oxide layers. It is found that the crystallinity of PZT film grown on LSCO electrode is much better than that on BLT film although the growth temperature of BLT/PZT/BLT is 100℃ higher than that of LSCO/PZT/LSCO. Remanent polarization of LSCO/PZT/LSCO capacitors measured at 10 V is 31.1 μC/cm~2, which is much higher than the value of 19.8 μC/cm~2 for BLT/PZT/BLT. Both kinds of the capacitors are fatigue-free up to 10~(10) switching cycles. The leakage current density measured at 5 V is about 4.7 x 10~(-6) A/cm~2 and 1.9 x 10~(-5) A/cm~2 for BLT/PZT/BLT and LSCO/PZT/LSCO, respectively. The differences for the two kinds of capacitors are discussed in the article.