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The objective of this study is to develop and verify a four electrode resistivity probe (4ERP) for the estimation of electrical properties of saturated soils without polarization at the electrodes. The 4ERP design is categorized by two types: wedge and plane. The wedge type is used for penetrating into the soil samples and the plane type is used for installing into experimental cells such as an oedometer cell. Consolidation tests are carried out on six different sized glass beads. The test results reveal that the shape factor, m, used in Archie’s law, is about 1.19 for glass beads. One-dimensional liquefaction tests show that the porosity obtained by the 4ERP is similar to the porosity determined by volume fraction. The porosity profile obtained by the penetration of the 4ERP into the large-scale calibration chamber in the clay-sand mixture is similar to the volume based porosity. Furthermore, the porosity profile estimated by the resistivity is almost the same as the volume based porosity in glass beads. This study demonstrates that the 4ERP may effectively estimate the porosity of saturated soils.

PZT(52/48) films are deposited by using an off-axis rf magnetron sputtering method on Pt/Ti/SiO2/Si(100) substrate. In order to decrease the microcracks which occurs on the surface of rf sputtered PZT films during postannealing at 600, 650 and 700°C, sol-gel derived 10% Pb excess Pb(Zr0.52Ti0.48)O3 layers are placed at the top and bottom of the rf sputtered PZT films, respectively. SEM micrographs reveal a drastic reduction of microcracks on the surface of the buffered PZT films. In addition, enhancement of crystallinity is also observed according to XRD analysis. The P-E hysteresis measurements show an increase in remanent polarization (12.1; 22.45, 34.64 μ C/cm2) and a decrease of the coercive field (108, 72.9, 68.3 kV/cm) with the increase of post-annealing temperature.

Pb(Zr0.53Ti0.47)O3(PZT) films have been deposited on Pt/Ti/SiO2and Pt/Ti/TiO2/polysilicon/ Si3N4/Si substrates. In the case of the Pt/Ti/TiO2/polysilicon/Si3N4/Si substrate, there are two different polycrystalline silicon layers. One has been postthermal annealed at 950°C for 30 min and the other has not had any thermal treatment after the deposition of the polycrystalline silicon. The hysteresis curve, piezoelectric coefficient (d33) and dielectric constant of the as-grown film were measured to characterize the electrical properties. Wide angle X-ray diffraction patterns and cross-sectional images of the films were used to investigate the structural properties. The d33of the PZT thin film on substrate A, which was postannealed at 950°C for 30 min after deposition of polycrystalline silicon, was measured to be 158 pm/V by the single beam laser interferometer method. A low frequency relative dielectric constant was 829. Remanent polarization and coercive field of the film on the substrate A were 39.5 C/cm2and 65.2 kV/cm, respectively. In addition, the interface of the PZT thin film on substrate A was more dense than that on substrate B, which was not postannealed after the deposition of polycrystalline silicon. This interface structure is very important during a chemical etching step. These results suggested that the substrate A is a very promising structure for microelectromechanical system devices based on the PZT thin film.