Electrical Characteristics of Metal–Ferroelectric–Semiconductor Structures Based on Poly(vinylidene fluoride)

Abstract

We prepared poly(vinylidene fluoride) (PVDF) films in the phase by a sol-gel method using PVDF solutions with different weight fractions. The electrical properties of PVDF films were studied for the possibility of using them in one-transistor (1-T)type ferroelectric random-access memories (FRAMs). In this research, the Au/PVDF/Si structure made from PVDF solution of 6 wt % concentration showed good ferroelectric and electrical properties. The memory window width and current density for the PVDF film from the 6 wt % PVDF solution were about 1.8 V and 10 À6 A/cm 2 for a bias voltage of 5 V, respectively. It is expected from these good ferroelectric properties that PVDF films will be suitable for low-cost 1-T-type FRAMs operating at a low voltage.

Direct Preparation of Nanoscale Thin Films of Poly(vinylidene fluoride) Containing β‐Crystalline Phase by Heat‐Controlled Spin Coating

“…Kim et al estimated the electrical characteristics of a metal‐ferroelectric‐semiconductor (MFS) capacitor based on thin PVDF films with a thickness of 25–180 nm, which were obtained on silicon substrates by spin coating the sol‐gel solution of PVDF prepared using DMF as a solvent. Although this report substantiated the characteristics of MFS structure, there neither was evidence provided to identify and confirm the presence of the β ‐phase nor were discussions made about the cause that favored the its formation 34. Since PVDF thin films with a thickness of 200 nm comprised dominantly of the γ ‐phase, prepared using the micro‐imprinting method, were also reported to exhibit fine ferroelectric characteristics,27 it is quite difficult to understand whether or not the polar β ‐phase really makes a contribution to the electrical properties of the thin films prepared by Kim et al Using the precursor solutions, prepared by dissolving PVDF in DMF, Kang et al fabricated ferroelectric PVDF thin films with thicknesses of 50–500 nm on gold substrate by humidity‐controlled spin casting, which was followed by rapid thermal annealing (RTA).…”

“…Among the common solution processing routes (e.g., spin coating, forming Langmuir‐Blodgett (LB) films, printing technology, etc. ), most recently, forming LB films30 and spin coating31–35 have been reported to favor the formation of PVDF thin films containing the β ‐crystalline phase. Moreover, for microelectronics applications, the well‐established spin‐coating method has been considered to be more suitable for fabricating smooth polymeric coatings on flat substrates36 on an industrial scale35 than the LB technique, which is generally considered to be time‐consuming37 and difficult when fabricating films of fluorine‐containing polymers, due to their rigidity and hydrophobicity 38…”

Epitaxially Grown Ferroelectric PVDF‐TrFE Film on Shape‐Tailored Semiconducting Rubrene Single Crystal

“…Kim and co‐workers fabricated an MFSM capacitor with various thicknesses of ferroelectric layer. The work shows that the capacitance did not decrease at high field when a film became thicker . We investigated the electrical properties of PVDF‐TrFE films as a function of film thickness (Figure S6, Supporting Information).…”

Preparation and Device Applications of Ferroelectric β-PVDF Films

“…The Au/PVDF/ Si structure fabricated by Kim et al showed good ferroelectric properties. The current density and memory window width for the PVDF film were about 10 −6 A/cm 2 and 1.8 V under a bias voltage of 5 V, respectively [80].…”