Leakage Current Suppression of Pt/Bi4_xLaxTi3O12/Ru Capacitors by Post-Annealing of Ru Films.

The effects of post-annealing on the properties of Ru films formed by metalorganic chemical vapor deposition were investigated, aiming to the application to the bottom electrode of ferroelectric capacitors. Ruthenium films were deposited at a temperature of 350°C using a liquid-type source of Ru[EtCp]2 without introducing O2. Post-annealing was performed in vacuum at a temperature of 400°C. Surface morphology and crystallinity of Ru were very similar between as-deposited and post-annealed Ru films. In addition, the Pt/BLT/Ru structure exhibits similar polarization hysteresis loops regardless of the annealing duration. However, leakage current density was drastically decreased as the annealing duration was increased. It is presumed from the thermal desorption spectroscopy that decrease of out-diffused gas from Ru film by post-annealing is a main reason for the improvement of leakage current characteristics. [ABSTRACT FROM AUTHOR]