Characteristics of Polycrystalline SrRuO[sub 3] Thin-Film Bottom Electrodes for Metallorganic Chemical-Vapor-Deposited Pb(Zr[sub 0.2]Ti[sub 0.8])O[sub 3] Thin Films

In situ and ex situ crystallized polycrystalline (SRO) thin-film electrodes are fabricated by dc magnetron sputtering at a substrate temperature of 550 and 350°C, respectively, followed by postannealing for application as bottom electrodes of metallorganic chemical-vapor-deposited (PZT) thin films. The in situ crystallized SRO electrode shows a negligible change in film composition during the subsequent annealing and works as a good electrode for the ferroelectric PZT films. However, the ex situ crystallization by postannealing largely decreases the Ru content in the SRO film and consequently the PZT film grown on top has a poor ferroelectric performance. In addition, the Zr component in the PZT film initially reacts with the excessive in the electrode, resulting in a deposition of at the initial stage of the PZT deposition which largely deteriorates the ferroelectric performance. Therefore, it is crucial to have in situ crystallized SRO for a reliable electrode of a PZT capacitor.