The Electrical Properties Of Ferroelectric Polymer-based Non-volatile Storage Structure

As novel functional materials, poly(vinylidene fluoride)(PVDF) and its copolymer with trifluoroethylene P(VDF-TrFE), have drawn much attention in recent years since they exhibit strong spontaneous polarization, excellent polarization stability and short switching time.We introduced MFeS and MFeOS structure as a kind of nonvolatile memory based on a ferroelectric copolymer, respectively and studied the topography with atomic force microscope (AFM) and electrical investigations on its electrical performance such as electrical fatigue and retention.1. The MFeS capacitor structure. The electrical fatigue phenomenon is observed during the fatigue process by using a self-made Sawyer-Tower circuit. It exhibits a strong frequency dependence of the fatigue voltage on the fatigue rate. As we concluded, the higher frequency the fatigue voltage has, the lower the fatigue rate is. In addition, we studied the effect of al bottom electrode and p-Si/al bottom electrode and gave our explanation to the observed phenomenon.2. The MFeOS capacitor structure. In our observations, the on/off ratio, memory window and C-V hysteresis changed during the fatigue processing. We found the on/off ratio became smaller and the memory window changed after a series of fatigue cycles. We tried to give our explanation of certain phenomenon. Besides, the retention is also studied. We find the change of voltage polarity, frequency and amplitude affect the retention performance in the nonvolatile memory.