Ferroelectric memory (FeRAM) has been identified as the most promising candidate to substitute flash memory and harddisk. Low power consumption, high endurance and high writing cycles are the key advantages of FeRAM. Organic ferroelectric memory has been drawing lots of research attention, due to its’ compatibility with flexible electronics, an emerging technology. Moreover, the material and processing costs are lower comparing with inorganic counterparts. Poly(vinylidene fluoride-co-trifluoroetheylene) (P(VDF-TrFE)) is being one of the most commonly adopted materials as the functional layer (thin film) for organic FeRAM. P(VDF-TrFE) has high Curie temperature, remnant polarization, feasibility to achieve low operating voltage, non-hazardous and low-cost potential, as well as co...[ Read more ]

Ferroelectric memory (FeRAM) has been identified as the most promising candidate to substitute flash memory and harddisk. Low power consumption, high endurance and high writing cycles are the key advantages of FeRAM. Organic ferroelectric memory has been drawing lots of research attention, due to its’ compatibility with flexible electronics, an emerging technology. Moreover, the material and processing costs are lower comparing with inorganic counterparts. Poly(vinylidene fluoride-co-trifluoroetheylene) (P(VDF-TrFE)) is being one of the most commonly adopted materials as the functional layer (thin film) for organic FeRAM. P(VDF-TrFE) has high Curie temperature, remnant polarization, feasibility to achieve low operating voltage, non-hazardous and low-cost potential, as well as convenience for fabrication (no post-processing required). However, the fabrication of P(VDF-TrFE) thin film was found to be difficult and typically suffering from various types of defects. One of the most critical defects was porous thin film resulting in high current leakage or even electrical breakdown.

To solve the porous thin film problem, the failure mechanism should firstly be identified. This thesis is intended to investigate the issue and to figure out the relationship between high humidity and porous thin film. The mechanism was explained by breath-figure effect highlighting the role of water droplets presence in air, both experimental study and molecular modeling were performed. Based on the results, research strategy was focused on solvent-free technique. Friction-transfer method was utilized to fabricate P(VDF-TrFE) thin films on Glass, ITO Glass and p-type Silicon substrates. Adhesion mechanism was proposed to explain the thin film transfer.

Surface morphology was observed by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM), while thin film thickness by Surface Profiler. The existence of ferroelectric beta-phase P(VDF-TrFE) was evidenced by X-Ray Diffraction (XRD). Piezo-response Microscopy (PFM) was used to prove the existence of ferroelectricity. Current-voltage characteristics was measured by a Sawyer-Tower Circuit. Polarization was calculated by the time integral of current density. The experimental results indicated that the remnant polarization was significantly higher than of spin-coated thin film. Shish-kebab structures were observed. The enhanced remnant polarization was explained by shear-induced crystallization. However, non-continuous thin film with numerous nano-particles were also observed for p-type Silicon substrate fabricated at high temperature, which was explained by solid-state dewetting mechanism.