EFFECT OF RUOX BOTTOM ELECTRODE ANNEALING TEMPERATURE ON SOL-GEL DERIVED PZT CAPACITORS

The effects of bottom electrode annealing temperature on ferroelectric capacitors are examined. Temperatures between 350 and 600 degrees C w ere used to anneal 2000 Angstrom RuO0.8/500 Angstrom Ti electrodes dep osited by ion beam sputtering. Anneals were performed in flowing O-2, N-2, ultra high purity (UHP) Ar, and air. Scanning Electron Microscope (SEM) data show that between 500 and 600 degrees C, in air and flowin g O-2, rectangular crystallites change to square crystallites. Energy Dispersive Spectroscopy (EDS) analysis shows that the square crystalli tes on the bottom electrodes annealed at 600 degrees C in flowing O-2 have a higher oxygen content than the surrounding matrix. Atomic Force Microscopy (AFM) data show that the bottom electrodes annealed in air and flowing O-2 are rougher (root mean square (RMS) roughness between 50 and 80 nm) compared to the bottom electrodes that are unannealed ( RMS roughness of 0.151 nm) and the bottom electrode annealed in flowin g N-2 (RMS roughness of 3.8 nm). SEM data show that the 600 degrees C bottom electrode anneal in UHP Ar resulted in a rougher surface, provi ding more nucleation sites for the PZT perovskite rosettes compared to the 400 degrees C bottom electrode anneal with all other experimental parameters equal.