FABRICATION AND PROPERTIES OF METAL-PZT-METAL CAPACITORS BY LIQUID DELIVERY MOCVD

ABSTRACT

Pb(Zr_1−x,Ti_x)O₃(PZT) thin films were prepared on 8-inch and 4-inch Pt or Ir-electroded Si wafers by liquid delivery metal-organic chemical vapor deposition (LD-MOCVD) using cocktail sources of Pb, Zr and Ti. The processing conditions were optimized in order to obtain high-performance PZT films. The thickness uniformity of PZT films on 8-inch substrate was about ± 3.24%. The deposition rate of Pb (15.8 nm/min) and Ti (17.9 nm/min) deposited on Si substrate were faster than that of Zr (2.5 nm/min). The growth temperature of PZT film was adjusted to 570–630°C depending on the substrates used. The properties of metal/PZT/metal capacitors were also studied. The PZT films based on Pt substrate showed no good ferroelectric properties. By contrast, the ferroelectric properties of Ir/IrO₂/PZT/IrO₂/Ir capacitors were excellent. At an applied voltage of 5 V, the remanent polarization (P_r) and coercive field (E_c) values were about 36 μ C/cm² and 50 kV/cm, respectively.

Keywords:

• Lead zirconate titanate
• ferroelectric thin films
• chemical vapor deposition
• electrical properties

ACKNOWLEDGMENTS

The authors are grateful for the financial support from National Natural Science Foundation of China (60601003) and (90407023), International cooperation project from Ministry of Science and Technology of China (2008DFA12000), and Ying Tong Education Foundation (101063). At the same times, many thanks to Mrs. S.Sun, Mr. Gary provost and Mr. G.S.Tompa from SMI for their technical support.