CHARACTERIZATION OF METAL-FERROELECTRIC-SEMICONDUCTOR STRUCTURE USING FERROELECTRIC POLYMER POLYVINYLIDENE FLUORIDE-TRIFLUOROETHYLENE (PVDF-TrFE) (51/49)

Abstract

In this work, we fabricated metal-ferroelectric-semiconductor (MFS) diodes with polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) (51/49) thin films for application to one transistor-type (1T-type) ferroelectric random access memories (FeRAMs). The thin films, with various thicknesses, were prepared on a silicon substrate by using a spin-coating method. The β-phase crystallinity and the grain size of the PVDF-TrFE increased as the film-thickness increased. Typical ferroelectric hysteresis loops were obtained from the capacitance-voltage (C-V) curves. These loops might be considered to be due to the ferroelectric nature of the PVDF-TrFE films. The values of the memory window width for 50-nm-, 150-nm-, and 350-nm-thick PVDF-TrFE films were about 1.4, 2.0, and 3.5 V for a bias sweeping from −5 V to 5 V, respectively. The values of the leakage current density, at a sweeping range of ±5 V, were about 2.7 × 10 −5 A/cm 2 , 1.1 × 10 −5 A/cm 2 , and 5.6×10 −6 A/cm 2 for 50-nm-, 150-nm-, and 350-nm-thick films, respectively. These results are useful and promising for realizing 1T-type FeRAMs operating at a low voltage.

A carrier-based analytical theory for negative capacitance symmetric double-gate field effect transistors and its simulation verification

“…Recently ferroelectric transistors were reported with under-thermal characteristics that presented [6] both hysteretic and non-hysteretic negative capacitance behaviors [7][8][9]. The difference between the reported devices and the transistor proposed by Salahuddin [1] is the insertion of a linear dielectric as a buffer layer due to the diffusion of the ferroelectric into the silicon [10]. We should clarify that the surface potential enhancement due to the ferroelectric's negative capacitance effect is entirely different from the amplifying effect on the tunneling current through the gate oxide as a result of the presence of a ferroelectric layer in tunneling read-only memory devices [11][12][13].…”

Large Piezoelectric Strain in Sub-10 Nanometer Two-Dimensional Polyvinylidene Fluoride Nanoflakes

“…The quantification of d 33 in sub-10 nm regime is still essential for technological advancements in (nano)­sensors and actuators. Owing to its advantages of high flexibility, wide frequency response, biocompatibility, low cost, high negative piezoelectric coefficient, and integration with traditional silicon-based (micro)-electronics, semicrystalline polymer PVDF has emerged as a promising substitute for conventional piezoceramics. PVDF has already attracted phenomenal research efforts for energy scavenging and sensing applications involving the development of electromechanical actuators, pressure sensors, and piezoelectric nanogenerators. , However, an effective phase transformation from thermodynamically stable α- to technologically favorable ferroelectric β-phase (all trans TTTT planar zigzag structure) must be achieved in order to gain enhanced piezoresponse from PVDF nanostructures.…”

Rapid Nanoimprinting and Excellent Piezoresponse of Polymeric Ferroelectric Nanostructures

“…1,29Ϫ31 While both values are smaller than those of inorganic piezoelec-tric ceramics, such as lead zirconate titanate (PZT), P(VDF-TrFE) copolymers are advantageous for their excellent solution processability, low annealing temperature, biocompatibility, and they can be easily integrated with both conventional siliconbased microelectronics and emerging organic electronics. As a result, they have been explored for a wide range of device applications, including piezoelectric transducers, 32 organic transistors, 33 electric capacitors, 10 nonvolatile memory cells, 3 and biomedical devices. 34 Thermal nanoimprinting is a simple process, yet it is able to create nanostructures as small as 5 nm.…”

“…Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer is an excellent class of ferroelectric material with spontaneous polarization close to 10 μC/cm 2 and piezoelectric coefficient d 33 around −38 pm/V at room temperature. ,− While both values are smaller than those of inorganic piezoelectric ceramics, such as lead zirconate titanate (PZT), P(VDF-TrFE) copolymers are advantageous for their excellent solution processability, low annealing temperature, biocompatibility, and they can be easily integrated with both conventional silicon-based microelectronics and emerging organic electronics. As a result, they have been explored for a wide range of device applications, including piezoelectric transducers, organic transistors, electric capacitors, nonvolatile memory cells, and biomedical devices…”