Simple Ru electrode scheme for ferroelectric (Pb,La)(Zr,Ti)O3 capacitors directly on silicon

A two-step process consisting of low temperature growth followed by rapid thermal annealing is demonstrated for Ru/(Pb,La)(Zr,Ti)O-3 (PLZT)/Ru ferroelectric capacitors directly on silicon. PLZT is a promising material for Gbit-scale ferroelectric memories, but its growth on silicon has proved challenging. The two-step process is designed to enable nucleation of perovskite phase PLZT while limiting diffusion which often leads to device failure. Minimization of stress and interdiffusion during film growth were necessary to optimize the remanent polarization. (Pb-4%La) (Zr0.3Ti0.7)O-3 capacitors with remanent polarizations up to 17 mu C/cm(2) were grown on Ru/Si at 400 degrees C and 50 mTorr O-2 using pulsed laser deposition. Direct high temperature growth (>600 degrees C) was not possible due to interface reactions, and film cracking was observed at low temperatures as well as at high and low oxygen pressures. (C) 1998 American Institute of Physics. [S0021-8979(98)00514-3].