Study On Hardware And Software Of Testing System Based On DC Power Amplifier For Ferroelectric Materials

Ferroelectric materials have many important properties, such as ferroelectric property, piezoelectric property, pyroelectric effect, electrooptic effect, acoustooptic effect, photorefractive effect, and some other nonlinear optics effects. Ferroelectric materials have very important practical and potential application in microelectonic and optoelectronic fields.In recent years, the preparation technology of ferroelectric materials, especially ferroelectric films, has been continually developed, and the application field of ferroelectric materials and devices has become larger and larger. More and more researchers are interested in ferroelectric materials and devices. They not only study the characteristics and improvement of the existing ferroelectric materials, but also explore and discover new ferroelectric materials. Therefore, researchers expect faster, more automatic, and more accurate measurement of the parameters of the ferroelectric materials and devices. It is necessary to study a computer-aided system for measuring ferroelectric material parameters.This system can measure both the I-V characteristics and the hysterisis loops of the ferroelectric ceramics and films. The measurement results including the figures and data can be transferred from the digital oscilloscope to the computer and then they can be processed ( such as saved, opened, and modified ). In contrast with the traditional oscilloscope which can also show and measure the parameters of ferroelectric materials, this system can save, open and modify the I-V curves, hysterisis loops, and data. It's more convenient and practical for the researchers to study different ferroelectric materials.Both the DC power amplifier in the measuring module, and the software for measuring I-V characteristics in the computer-aided system for measuring ferroelectric material parameters are mainly discussed in this thesis. High voltage should be applied to the two electrodes of ferroelectric ceramics for measuring its I-V characteristic. The polarization switching of ferroelectric ceramics is much slower than ferroelectric films. If the frequency of the measuring signal is very high, the polarization of ferroelectric ceramics cannot follow the fast-varying electric field. Therefore, in order to measure the I-V characteristic of both ferroelectric ceramics and films, we have to use a DC power amplifier whose frequency ranges from 0.01 to 100kHz.Using the software for measuring I-V characteristics, we can not only calculate the ferroelectric sample parameters, but also compensate leak conductance and linear capacitance of the ferroelectric sample in order to show intrinsic I-V curve.