MICROSTRUCTURE OF PZT SOL-GEL FILMS ON PT SUBSTRATES WITH DIFFERENT ADHESION LAYERS

The influence of Ta, Ti and TiO2 adhesion layers with Pt bottom electr odes and the deposition temperature of the metallization on the nuclea tion and growth of sol-gel derived Pb(Zr0.53Ti0.47)O-3 thin films is r eported. Several different PZT annealing profiles were simultaneously investigated to determine the role of PZT annealing on resultant PZT f ilm microstructures for a given metallization. The adhesion layer was found to primarily influence PZT grain size. Largest grain sizes were observed for substrate structures with TiO2 adhesion layers. Slower he ating rates resulted in rosette type structures and a large volume of residual pyrochlore, particularly in the case of TiO2 adhesion layers, while yielding only a grain size increase on Ti and Ta bonded substra tes. These results were correlated to the stability of the adhesion la yers in terms of diffusion through Pt and thus changes in the chemistr y and structure of the film/Pt interface where the perovskite nucleati on was observed to occur. The Pt metallizations were found to be more strongly (111) textured on the purely metallic adhesion layers and ind ependent of the adhesion layer deposition temperature. PZT texture was found to be influenced by adhesion layer deposition temperature and P ZT annealing profile. The perovskite texture was altered through annea ling conditions only on TiO2 bonded substrates. The above results sugg ested a reduction of the number of perovskite nucleation sites on meta llizations with TiO2 adhesion layer. This result is in agreement with Rutherford backscattering evidence from previous investigations.