Abstract
There are many methods to prepare PZT films. For examples, tape casting can be used to prepare films with thickness above 10 μm, and PVD methods can be used for films below 1μm thickness. However, it is difficult to prepare films of thickness between 1μm and 10μm by traditional methods. Therefore, the purpose of this study is to investigate new methods for depositing PZT films between 1μm and 10μm efficiently and inexpensively. The preparing methods we choose were MOD method and EPD method.In preparing PZT films by MOD method, we have tried to investigate the thickness variation and electrical properties by comparing the cases with/without sol-gel PZT nano-powder. In both cases, the concentrations of precursor and PZT nano-powder were controlled. In the case without addition to PZT nano-powder, the best concentration of precursor was 0.3M, and an average layer thickness of 0.3μm was obtained. In P-E curve measurements, the Pr values for single layer to 9-layer deposit were in the range 12.2~28.99μC/cm2. In the case with PZT nano-powder addition, the optimum the concentrations of precursor and nano-powder were kept at 0.25M and 0.05M, respectively. The average thickness of each deposited layer was 0.68μm, and the Pr value ranged from 22 to 33.6μC/cm2. Adding PZT nano-powder was verified to be advantageous in increasing layer thickness and electrical polarization. However, protrusion was observed after thermal annealing that may cause problem when applying the films for device manufacturing.In the EPD process, we have chosen two kinds of powder, a commercial one and the other produced by sol-gel method, for film deposition. For each kind of powder, we found that films were deposited well when the powder was mixed in methyl acetate to the concentration of 5wt% with applying dc voltage 24V. The film thickness of deposition for 3 minutes by using commercial and sol-gel powders was 5.4μm and 3.3μm, respectively. After high temperature sintering, the electrical property of films prepared by EPD method could not be measured. The reason may come from the short-circuit effect due to the high degree of porosity in the films.