Measuring And Modeling Of Ferroelectric Capacitor

In this dissertation, based on the C~V, Q~V and I-V characteristics of ferroelectric capacitor, the methods to describe its performance are introduced. The new eight parameters of ferroelectric capacitor are also defined. From the view of theory, the relationships among C~V, Q~V and I~V characteristic and the relationships among these parameters of ferroelectric capacitor are deduced.At present, the measurement system of ferroelectric capacitor has two disadvantages. The one is that the measured hysteresis (Q~V curve) of ferroelectric capacitor has a error, and the other is that this hysteresis has a gap if the measured circuit is the ferroelectric capacitor in series with a linear resistor. The first is deduced by the asymmetry of ferroelectric capacitor's polarization and it is difficult to eliminate this error. The latter is deduced by the direct excursion of the measurement system and this gap can be eliminated by the data process method. A measurement system is set up and it can demonstrate the C~V, Q~V and I~V curves as well as the parameters of ferroelectric capacitor. Of course, the gap of hysteresis is eliminated.The models of ferroelectric capacitor have a disadvantage, which is that when the amplitude of the voltage is enough large the ferroelectric capacitor will be saturated. This is conflict with the measurement result. Based on the measurement result and the advantages of modeling methods of Miller and Lim, a new modeling method is brought forward without this disadvantage.