Thick Films of Pb(Mg,Nb)TiO by Aerosol Combustion

ABSTRACTThick films of solid solutions of lead-magnesium-niobium-oxide (PMN) and lead-titanate (PTO) were deposited by aerosol combustion. Films consisted of submicron ceramic particles synthesized by combustion of a metalorganic solution in a methane-oxygen flame. The particulate material was deposited on heated substrates (200°C) and subsequently sintered at elevated temperatures. Results varied with starting chemistry and sintering conditions. As-deposited materials were mixed perovskite-pyrochlore phase. Sintering at low temperatures produced pure perovskite material that was not completely dense. Sintering at high temperatures produced dense ceramics of pyrochlore material. This technique requires further optimization for direct deposition of continuous films, but is immediately suitable for producing fine powders for tape casting of capacitors, etc.

Pulsed Laser Deposition of High-Epsilon Dielectrics: PMN and PMN-PT

ABSTRACTIn this study we report on the KrF excimer laser deposition of crystalline films of lead magnesium niobium oxide (PMN) and solid solutions of PMN and lead titanate (PT) in a 65:35 ratio. These materials have potential microelectronic applications as thin film capacitors due to their high dielectric constants (εPMN(bulk) ≥ 10,000). Films were typically deposited in an oxygen background at elevated substrate temperatures(Ts = 525 °C) on substrates of Pt(111)/SiO2/Si or Pt(111)/glass. The deposited films were characterized by Rutherford Backscattering Spectroscopy (RBS), x-ray diffraction, and capacitance/loss measurements. Films prepared from a nearlystoichiometric commercial PMN target were low in Mg and Pb and yielded only the low-c pyrochlore phase (measured εfilm ≃ 100), even after cx-situ annealing at temperatures up to 650°C. Films deposited from Pb,Mg-rich targets prepared by a sol-gel process (tailored to produce the desired film stoichiometry) contained mixtures of perovskite and pyrochlore, with typical r values of order 600–1200.