Characterization of LSCO/Ir and LSCO/Ru structure as diffusion barrier layers for highly integrated memory devices

Abstract

The integration of ferroelectric capacitors into memory cells requires the bottom electrode material to be placed directly over a contact plug. LaSrCoO3 (LSCO) thin film was deposited using dc magnetron sputter-deposition as an electrode material and a diffusion barrier layer for Pb(Zr,Ti)O-3 (PZT) thin-film capacitors. The thermal stability and barrier property of LSCO/Ir/poly-Si and LSCO/Ru/poly-Si contact layers for oxygen diffusion were investigated by Auger electron spectroscopy to find a structure suitable for the bottom electrode of integrated ferroelectric capacitors. The LSCO/Ir/poly-Si composite stack showed lower resistivity compared to LSCO/Ru/poly-Si structure and provided good fatigue performance for PZT capacitors. From these results, the LSCO/Ir/Poly-Si is thought to be the available structure for the fabrication of high-density ferroelectric memory. (C) 2003 The Electrochemical Society.