Low temperature growth and reliability of ferroelectric memory cell integrated on Si with conducting barrier stack

Polycrystalline LSCO/PNZT/LSCO ferroelectric capacitor heterostructures were grown by pulsed laser deposition using a composite conducting barrier layer of Pt/TiN on poly-Si/Si substrate. The growth of the ferroelectric heterostructure is accomplished at a temperature in the range of 500-600°C. This integration results in a 3-dimensional stacked capacitor-transistor geometry which is important for high density nonvolatile memory (HDNVM) applications. Transmission electron microscopy shows smooth substrate-film and film-film interfaces without any perceptible interdiffusion. The ferroelectric properties and reliability of these integrated capacitors were studied extensively at room temperature and 100°C for different growth temperatures. The capacitors exhibit excellent reliability, both at room temperature and at elevated temperatures, making them very desirable for HDNVM applications.