Liquid delivery metal-organic chemical vapor deposition of Pb(ZrxTi1-x)O3 thin films for high-density ferroelectric random access memory application

The growth characteristics of Pb(ZrTi1-x)O-3 (PZT) thin films were investigated for application to high-density ferroelectric random access memories (FeRAM) devices. Films were grown by the liquid source metal-organic chemical vapor deposition (LS-MOCVD) method with tmhd-family precursors, such as Pb(tmhd)(2), Zr(tmhd)(2)((OPr)-Pr-i)(2) and Ti(tmhd)(2)((OPr)-Pr-i)(2), dissolved in octane. Film deposition was mainly performed at 560degreesC, because it is the highest temperature at which bottom electrode contact could be maintained against oxidation in our capacitor over bit-line (COB) structure. The control of Pb precursor supply plays the most critical role in realizing a reliable process or PZT thin film deposition. We have monitored the changes in the microstructure and electrical properties of films on increasing the Pb precursor supply into the reaction chamber. Under optimized conditions, Ir/IrO2/PZT(100 nm)/Ir capacitor shows well-saturated hysteresis loops with a remanent polarization (Pr) of similar to28 muC/cm(2) and coercive voltage of 0.8 V at 2.5 V.