Search query: Flexible ultra-short channel organic ferroelectric non-volatile memory transistors

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abstract: Ferroelectric non volatile memory devices are the most promising type of memory for future use in commercial applications. However, conventional planar organic ferroelectric memory transistors usually show poor performance in current density, operating speed and mechanical stability. There are three main factors which restrict the performance of organic ferroelectric memory transistors: the intrinsic low charge mobility of the organic semiconductor material; the large surface roughness of the ferroelectric layer; and the relative long channel length. In this research, a novel device architecture with an ultra short channel length was invented. Benefiting from the short channel length, the memory device devised in this research exhibits a large current density of up to 6.32 mA cm 2 and a fast operating speed. Furthermore, the current flows across the semiconductor layer from the bottom mesh source electrode to the top drain electrode, which reduced the influence of the poor interface quality caused by the use of poly(vinylidene fluoride co trifluoroethylene) [P(VDF TrFe) and enhances the performance of mechanical stability under bending. In addition, the main memory properties are comparable or superior to previously reported organic ferroelectric memories and inorganic ferroelectric memory with a vertical structure. Therefore, benefiting from the ultra short channel length and special device structure, the ferroelectric memory in this research exhibited a large driving force, excellent bending characteristics and outstanding storage performance, which has great potential for wearable and flexible electric devices.
author_names: Enlong Li

Xiaomin Wu

Shuqiong Lan

Qian Yang

Yuan Fang

Huipeng Chen

Tailiang Guo
title: Flexible ultra short channel organic ferroelectric non volatile memory transistors
year: 2019

abstract: We fabricated ultra flexible organic non volatile ferroelectric field effect transistors (FeFETs) with poly(vinylidene fluoride trifluoroethylene) [P(VDF TrFE) on polyimide substrates, which adopted a solution based top contact/bottom gate structure for low cost process without patterning. P(VDF TrFE) gate dielectric layers and regioregular poly(3 hexylthiophene) active layers were formed by the spin coating method. The field effect mobility (m FE) was ~0.28 cm2/V s, the on/off ratio was approximately 5.6 x 103, and the memory window (threshold voltage shift) was approximately 7 V. In addition, FeFETs were operated even at small bend radii without considerable changes in these values.
author_names: Min Gee Kim

Dae-Hee Han

Kyung Eun Park

Byung-Eun Park
title: Solution processed organic ferroelectric field effect transistors on ultra flexible substrates
year: 2016

abstract: The flexible organic non volatile ferroelectric field effect transistors (FeFETs) with poly(vinylidene fluoride trifluoroethylene) [P(VDF TrFE) was fabricated on polyimide and aluminum foil substrates. Al foil has merit of flexibility because of ultraflexible and ultrathin properties. It can be bent with small bend radius and even folded. It serves as bottom gate electrode in itself as well. Thus, an expensive fabrication step, evaporation of bottom gate, can be removed. In spite of these merits of Al foil, it is difficult to fabricate FeFETs on it owing to difficulty in handling: Al foil wrinkles easily and cannot be flattened during fabrication. The regioregular poly(3 hexylthiophene) [P3HT] film was formed as an active layer by the sol gel method at low temperature. In case of the fabricated FeFETs on polyimide substrates, the field effect mobility was ~0.28 cm2/Vs, the on/off ratio was approximately 5.6 x 103, and the memory window (threshold voltage shift) was approximately 7 V. It has ~103 of current on/off ratio and about 7 8 V of memory window for the Al foil substrates.
author_names: Dae-Hee Han

Min Gee Kim

Byung-Eun Park
title: Non volatile Organic Ferroelectric Field Effect Transistors Fabricated on Al Foil and Polyimide Substrates
year: 2020

abstract: In this letter, we propose one transistor ferroelectric NOR type (Fe NOR) non volatile memory based on HfZrOx ferroelectric FETs (FeFETs) The enhanced drain channel coupling in ultra short channel FeFETs is utilized to dynamically modulate the memory window of storage cells, thereby resulting in simple erase program and read operations. The simulation analysis predicts sub 1V program/erase voltages in the proposed Fe NOR memory array and, therefore, presents a significantly lower power alternative to conventional FeRAM and NOR flash memories.
author_names: Ankit Sharma

Kaushik Roy
title: 1T Non Volatile Memory Design Using Sub 10nm Ferroelectric FETs
venue: IEEE Electron Device Letters
year: 2018

abstract: Abstract Printing device arrays of the non volatile memory transistors is highly desired in the roll to roll manufacturing of integrated circuits. Here, we demonstrate the utilization of an insulating biomacromolecule of DNA in the printed transistor memory. A new DNA derivative was synthesized via an ion exchange reaction in the aqueous solution. Homogeneous molecular orientation in DNA derivative was achieved through a solution process in butanol, which can be employed as the dielectric with a densely packed structure and a good insulating property. The engineered DNA derivative enables to fabricate integrated organic thin film transistor (OTFT) memories on a large area flexible substrate in ambient atmosphere. Combining the results of low frequency dependence of capacitance and a retention time of more than 100 s, this solution processed DNA complex was revealed to be a ferroelectric like dielectric. The printed memories exhibit hole mobility of 0.65 cm2V 1s 1 and a large memory window up to 13 V, which is enough for a plenty of applications. Therefore, this approach is promising for printing large scale flexible OTFT memories and for realizing various integrated electronics.
author_names: Lijuan Liang

Xuying Liu

Masayuki Kanehara

Norihisa Kobayashi

Takeo Minari
title: Layer by layer printing non volatile organic thin film transistor memory with a planarly oriented DNA complex dielectric
year: 2018

abstract: Scalable circuits of organic logic and memory are realized using all additive printing processes. A 3 bit organic complementary decoder is fabricated and used to read and write non volatile, rewritable ferroelectric memory. The decoder memory array is patterned by inkjet and gravure printing on flexible plastics. Simulation models for the organic transistors are developed, enabling circuit designs tolerant of the variations in printed devices. We explain the key design rules in fabrication of complex printed circuits and elucidate the performance requirements of materials and devices for reliable organic digital logic.
author_names: Tse Nga Ng

David E Schwartz

Leah L Lavery

Gregory L Whiting

Beverly Russo

Brent Krusor

Janos Veres

Per Broms

Lars Herlogsson

Naveed Alam

Olle Hagel

Jakob Nilsson

Christer Karlsson
title: Scalable printed electronics: an organic decoder addressing ferroelectric non volatile memory
venue: Scientific reports
year: 2012

abstract: The modern generation of data storage technology brings new challenges to existing materials for low power data processing, reliable, fast and sizable transfer of data1. In this context, artificial multiferroic composites based on ferromagnetic (FM) and ferroelectric (FE) phases that exhibit strong magnetoelectric coupling, hold promise for designing new generation memory devices with several advantages. Multiferroic composites offer innovative approaches for non volatile memory devices as compared to their semiconductor transistor based competitors2. The organic thin memories are particularly favorable due to their environment friendly nature, low fabrication cost and mechanical flexibility3. Here, a room temperature paradigm two level nonvolatile memory operation have been demonstrated by utilizing the nonlinear magnetoelectric effects in flexible multiferroic SmFeO3/P(VDF TrFE) nanocomposite films. Strain induced interface interactions between ferromagnetic and ferroelectric phases in SmFeO3/P(VDF TrFE) nanocomposite films allow electric field controlled magnetization behaviour. The sign of magnetoelectric coupling coefficient (a) for the composite films can be repeatedly switched between positive and negative by applying electric fields. This can be used to store binary information for non volatile memory devices. The magnetoelectric response and the required voltage for switching of a can be tuned by varying the magnetic phase fraction (SmFeO3 nanoparticles) in nanocomposite films. Hence, flexible magnetoelectric SmFeO3/P(VDF TrFE) nanocomposite films can be utilized for nonvolatile memory applications with practical characteristics such as simple compact structure, easy reading/writing operation, fast speed and low power consumption.
author_names: Anju Ahlawat
title: Flexible magneto electric nanocomposite films for possible non volatile memory applications
year: 2020

title: Ultra Flexible Organic Non volatile Ferroelectric Transistor Memory
year: 2013

abstract: In this work, metal ferroelectric semiconductor field effect transistors (MFSFETs) have been fabricated for the first time using poly(vinylidene fluoride) (PVDF) and polyvinylidene fluoride trifluoroethylene [P(VDF TrFE) thin films as ferroelectric layers. PVDF and P(VDF TrFE) thin films were fabricated by a sol gel method on Si(100) wafers. The drain current gate voltage (I D V G characteristics of both MFSFETs fabricated with PVDF and P(VDF TrFE) thin films exhibited very good ferroelectric hysteretic curves with a counterclockwise loop that is the same as those of other ferroelectric materials. It also demonstrates the realization of a one transistor type (1T type) ferroelectric memory without a buffer layer using thin organic material. The absence of a buffer layer presents many advantages such as the elimination of the depolarization field, leakage current influence of the thin buffer layer, reduction of the process steps, low operational voltage, and low power consumption. MFSFETs using PVDF and P(VDF TrFE) thin films as ferroelectric layers have promising potential for use in low voltage and flexible 1T type ferroelectric random access memory (FeRAM) using organic material.
author_names: Byung-Eun Park
title: Non volatile Ferroelectric Memory Transistors Using PVDF and P(VDF TrFE) Thin Films
year: 2016

abstract: Organic optical transistor memory (OTM) devices are receiving extensive attention for application in electronics due to low power consumption and high density storage. However, in conventional organic OTM devices, the photogenerated carriers in the organic semiconductor layer tend to recombine due to the long channel length (usually tens of micrometers) causing a reduced separation efficiency of photogenerated carriers and subsequent small memory windows, which limit their application in optical storage. In this work, a multilevel non volatile optical memory device based on a vertical thin film transistor was reported, for which the channel length was successfully downscaled to the nanoscale (tens of nanomenters) It significantly increased the separation efficiency of photogenerated charges, leading to an admirable memory window of 73 V accompanied by enhanced memory ratios, six distinct storage levels along with high responsivity and photosensitivity at low optical power. Moreover, the flexible OTM device exhibited excellent mechanical robustness due to its vertical design, which was much less impacted by the dislocations and in plane cracks during the mechanical bending process. Furthermore, a logic gate with 'AND' and 'OR' operations was realized by a single memory device through two optical pulses and an optical memory array was demonstrated to realize the functions of image processing and recognition. This work offers a promising method to fabricate high performance OTM devices, which show great potential in the development of multilevel data storage and image processing.
author_names: Xiaomin Wu

Shuqiong Lan

Daobing Hu

Qizhen Chen

Enlong Li

Yujie Yan

Huipeng Chen

Tailiang Guo
title: High performance flexible multilevel optical memory based on a vertical organic field effect transistor with ultrashort channel length
year: 2019