Integration Of Si-based Ferroelectric Capacitors With Ti-Al Conductive Barrier Layer

Pt/La0.5Sr0.5CoO3/Pb(Zr0.4Ti0.6)O3/La0.5Sr0.5CoO3/Ti-Al/Si （Pt/LSCO/PZT/LSCO/Ti-Al/Si）ferroelectric capacitor heterostructure was fabricated by magnetron sputtering and Sol-geltechnique on Si substrate using Ti-Al film as a conducting barrier layer. The ferroelectricproperties of the samples was investigated using a precision LC unit from RadiantTechnologies. It is found that remanent polarization and smaller coercive voltage, measuredat5V, are32.4μC/cm2and1.1V, respectively. Moreover, this capacitor possesses very goodfatigue-resistance and retention properties, meeting the requirements of device application.Various lead excess of PZT precursors were used to prepare PZT film using Sol-gelmethod, and the switching properties of the LSCO/PZT/LSCO capacitor were investigated.It is found that LSCO/PZT/LSCO capacitor corresponding to15%lead excess precursorvielded the best properties, compared with the samples using5%and25%excess leadprecursors. The coercive voltage and remnant polarization of LSCO/PZT/LSCO capacitorsmeasured at5V are1.25V and24.6μC/cm2, respectively. No obvious fatigue can be foundup to109swithing cycles for all the samples, and the resistivity of the LSCO/PZT/LSCOcapacitor decreases with the increase of lead excess.Highly oriented (001) Ti3Al film was prepared on Si (111) substrate, and impact ofgrowth temperature on film microstructure of Ti3Al film is investigated. It is found that theoptimal growth temperature for growth of highly oriented Ti3Al film is630℃.Moreover,LSCO/PZT/LSCO ferroelectric capacitor with good microstructure and ferroelectricproperties was successfully grown on Ti3Al/Si substrate.