Low-temperature integration of lead-based ferroelectric capacitors on Si with diffusion barrier layer

Publication Type:

Journal Article

Authors:

B.T. Liu; K. Maki; S. Aggarwal; B. Nagaraj; V. Nagarajan; L. Salamanca-Riba; Ramamoorthy Ramesh; A.M. Dhote; O. Auciello

Source:

Applied Physics Letters, Volume 80, Number 19, p.3599-3601 (2002)

Keywords:

aluminum, Amorphous films, Amorphous materials, Barrier layers, Bottom electrodes, Capacitors, Concentration of dissolved oxygen, Conducting barriers, Conductive films, Crystallinities, deposition, Deposition pressures, Diffusion barrier layers, Diffusion barriers, Dissolved oxygen, Electron energy loss spectroscopy, Energy dissipation, Ferroelectric capacitors, Ferroelectric devices, Ferroelectric films, Ferroelectric property, ferroelectricity, High power density, integration, lead, Lead zirconate titanate thin films, Low Power, Low temperatures, Non-volatile ferroelectric memories, Pb(Zr, polycrystalline, Power densities, PZT film, Semiconducting lead compounds, Semiconducting silicon compounds, Si wafer, Silicon substrates, Silicon transistors, Silicon wafers, Sol-gel process, Sputtering conditions, Sputtering power, Ti)O, zirconium

Abstract:

Ferroelectric lead zirconate titanate thin films have been integrated on silicon substrates using Ti-Al-based conducting diffusion barriers produced by sputter deposition. The microstructure of the Ti-Al barrier layer was systematically altered through changes in the sputtering conditions, specifically the power density and deposition pressure. We find that the crystallinity of the Ti-Al film strongly correlates with sputtering power density and ambient i.e., it is amorphous at low power density and/or high deposition pressure, and polycrystalline at high power density and/or low deposition pressure. Electron energy loss spectroscopy studies demonstrate that the amorphous Ti-Al (a-Ti-Al) films contain a higher concentration of dissolved oxygen than crystalline Ti-Al. A low temperature sol-gel process has been used to prepare Pb(Zr,Ti)O3 PZT films at 450°C on conducting Si wafers with a-Ti-Al conducting barrier layer and La-Sr-Co-O top and bottom electrodes. The excellent ferroelectric properties obtained with the a-Ti-Al barrier provide a promising approach for integration of PZT-based capacitors with silicon transistor technology for the fabrication of nonvolatile ferroelectric memories. © 2002 American Institute of Physics.

Notes:

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