A System For Measuring The Ferroelectric Materials' Electrical Parameters By Digital Osciloscope

The electrical properties of ferroelectric materials are showed by the hysteresis loop, I-V characteristic and switching characteristic primarily. The hysteresis loop presents the relation between polarization and electric field. The I-V characteristic presents the relation between current and voltage. The switching characteristic presents the relation between current and time.The thesis focuses on developing a computer-aided system for measuring the ferroelectric materials'electrical parameters. The whole system consists of two parts: hardware and software.The function of the hardware is to measure the electrical properties of ferroelectric materials and to control the device for measuring the ferroelectric materials'electrical parameters,and to collect these original data. This part consists of three modules: the module of ferroelectric properties measuring, digital storage oscilloscope and control module. The module of ferroelectric properties measuring is comprised of signal generator, equalizer, buffer, power amplifier and high voltage generator. It can generate many kinds of signals such as sine wave, triangular wave, rectangular wave and bipolar double pulse. All these waves are basic stimulant signals for measuring the ferroelectric properties. The functon of digital storage oscilloscope is to display waveform and collect data.Control module is made of PCI-1734 card and logic control circuit,and completes the function of pbutton and knob.System software consists of communication and interface module: the communication module functions initializing digital oscilloscope and reading the data from digital oscilloscope. The interface module is made up of loading window, decaying window,main window and parameter setting window, the system can accomplish moving the single-channel and synthetic curves, switching the two types mentioned above. The system can play waveform analysis, phase shifting and centrosymmetry of the synthetic curves; Calculate ferroelectric electrical parameters; save and print waveform data such as sample capacitor, sample thickness, sample dimension and so on. The system makes the comparison between different samples more conveniently.