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

A two-step process consisting of low temperature growth followed by rapid thermal annealing is demonstrated for $Ru/(Pb,La)(Zr,Ti)O3 (PLZT)/Ru$ 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. $(Pb-4%La)(Zr0.3Ti0.7)O3$ capacitors with remanent polarizations up to $17 μC/cm2$ were grown on Ru/Si at 400 °C and 50 mTorr $O2$ using pulsed laser deposition. Direct high temperature growth (>600 °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.