Direct integration of sol-gel derived ceramic films with porous silicon, without buffer layers, has been demonstrated. The effects of ceramic type, solvent type, solution concentration, as well as, porous silicon layer thickness, porosity and preparation conditions, on the quality and microstructure of sol-gel films/porous silicon integrated systems have been studied. The following ceramic compositions have been applied to porous silicon as protective coatings: PZT (PbZr0.3Ti0.7O3), PLZT (Pb0.925La0.055Zr0.3Ti0.7O3), ZrO2, TiO2, with 2-methoxyethanol and 2-ethoxyethanol solvents, 0.5 and 0.1 M precursor solution concentrations. The LSCO (La0.5Sr0.5CO.3) water based sol-gels have been deposited for electroconductive purposes.The best compositions for integration, giving transparent, mirror-like, uniform ceramic films with fine morphology and strong adhesion, were found to be the TiO2 and ZrO2 as well as, the diluted (0.1 M) PZT (PbZr0.3Ti0.7O3) sol-gel precursors. Conductive LSCO sol-gel derived films showed improved wetting and stronger adhesive interaction with porous silicon, as compared to polished silicon wafers.

No abstract

No abstract

Chemical solution-deposited thin films of PbZr(0.53)Ti(0.47)O(3)/La(0.5)Sr(0.5)CoO(3) on Pt/TiO(2)/SiO(2)/Si substrates have been investigated by dynamic SIMS. The PbZr(0.53)Ti(0.47)O(3) (PZT) is intended to serve as a ferroelectric layer for microelectronic or microelectromechanical applications; conducting La(0.5)Sr(0.5)CoO(3) (LSCO) is a buffer layer intended to eliminate fatigue effects which usually occur at the Pt/PZT interface. Depth profiles of the main components were obtained and revealed that significant diffusion occurred during the deposition and crystallisation processes. Two types of sample, with different thickness of PZT and different types of poly(vinyl alcohol) (PVA) added to the LSCO precursor, were investigated.

PbZr0.53Ti0.47O3 (PZT) films on La0.5Sr0.5CoO3 (LSCO) /Pt electrodes crystallize in the perovskite phase at 550°C. Cross section SEM shows a columnar grain structure of PZT films on fine-grained LSCO. The ferroelectric response of the heterostructures depends on the annealing temperature of the LSCO layer. The remanent polarization and coercive field of the PZT annealed at 550 °C deposited on LSCO annealed at 800 °C are 25 μC/cm2 and 99 kV/cm respectively, comparable to the values obtained for PZT films on platinized silicon substrate.