• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.118-118
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• 2011

The Nano-Floating Gate Memory(NFGM) devices with ZnO:Cu thin film embedded in Al2O3 and AlOx-SAOL were fabricated and the electrical characteristics were evaluated. To further improve the scaling and to increase the program/erase speed, the high-k dielectric with a large barrier height such as Al2O3 can also act alternatively as a blocking layer for high-speed flash memory device application. The Al2O3 layer and AlOx-SAOL were deposited by MLD system and ZnO:Cu films were deposited by ALD system. The tunneling layer which is consisted of AlOx-SAOL were sequentially deposited at $100^{\circ}C$. The floating gate is consisted of ZnO films, which are doped with copper. The floating gate of ZnO:Cu films was used for charge trap. The same as tunneling layer, floating gate were sequentially deposited at $100^{\circ}C$. By using ALD process, we could control the proportion of Cu doping in charge trap layer and observe the memory characteristic of Cu doping ratio. Also, we could control and observe the memory property which is followed by tunneling layer thickness. The thickness of ZnO:Cu films was measured by Transmission Electron Microscopy. XPS analysis was performed to determine the composition of the ZnO:Cu film deposited by ALD process. A significant threshold voltage shift of fabricated floating gate memory devices was obtained due to the charging effects of ZnO:Cu films and the memory windows was about 13V. The feasibility of ZnO:Cu films deposited between Al2O3 and AlOx-SAOL for NFGM device application was also showed. We applied our ZnO:Cu memory to thin film transistor and evaluate the electrical property. The structure of our memory thin film transistor is consisted of all organic-inorganic hybrid structure. Then, we expect that our film could be applied to high-performance flexible device.----못찾겠음......

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.440-440
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• 2011

We report on the non-volatile memory characteristics of a bistable organic memory (BOM) device with Au nanoparticles (NPs) embedded in a conducting poly N-vinylcarbazole (PVK) colloids hybrid layer deposited on flexible polyethylene terephthalate (PET) substrates. Transmission electron microscopy (TEM) images show the Au nanoparticles distributed isotropically around the surface of a PVK colloid. The average induced charge on Au nanoparticles, estimated using the C-V hysteresis curve, was large, as much as 5 holes/NP at a sweeping voltage of ${\pm}3$ V. The maximum ON/OFF ratio of the current bistability in the BOM devices was as large as $1{\times}105$. The cycling endurance tests of the ON/OFF switching exhibited a high endurance of above $1.5{\times}105$ cycles and a high ON/OFF ratio of ~105 could be achieved consistently even after quite a long retention time of more than $1{\times}106$ s.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.7
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• pp.615-619
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• 2008

A molecular memory device which has a structure of Al/$Al_2O_3$/ASA-15 LB monolayer/Ti/Al device, was fabricated. To study a charge transfer mechanism of molecular memory devices, current density-voltage (J-V) characteristics were measured at an increasing temperature range from 10 K to 300 K with an interval of 30 K. Strong temperature-dependent electrical property and tunneling through organic monolayer at low bias (below 0.5 V) were appeared. These experimental data were fitted by using a theoretical formula such as the Simmons model. In comparison between the theoretical and the experimental results, it was verified that the fitting results using the Simmons model about direct tunneling was fairly fitted below 0.5 V at both 300 K and 10 K. Hopping conduction was also dominant at all voltage range above 200 K due to charges trapped by defects located within the dielectric stack, including the $Al_2O_3$, organic monolayer and Ti interfaces.

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.05a
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• pp.21.1-21.1
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• 2006

• Journal of the Microelectronics and Packaging Society
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• v.20 no.2
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• pp.1-9
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• 2013

Recently flexible electronic devices have attracted a great deal of attention because of new application possibilities including flexible display, flexible memory, flexible solar cell and flexible sensor. In particular, development of flexible memory is essential to complete the flexible integrated systems such as flexible smart phone and wearable computer. Research of flexible memory has primarily focused on organic-based materials. However, organic flexible memory has still several disadvantages, including lower electrical performance and long-term reliability. Therefore, emerging research in flexible electronics seeks to develop flexible and stretchable technologies that offer the high performance of conventional wafer-based devices as well as superior flexibility. Development of flexible memory with inorganic silicon materials is based on the design principle that any material, in sufficiently thin form, is flexible and bendable since the bending strain is directly proportional to thickness. This article reviews progress in recent technologies for flexible memory and flexible electronics with inorganic silicon materials, including transfer printing technology, wavy or serpentine interconnection structure for reducing strain, and wafer thinning technology.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.195.2-195.2
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• 2013

플라즈마 중합 증착기술을 이용하여 ppMMA (plasma polymerized methyl methacrylate) 및 ppS (plasma polymerized styrene) 박막을 제작하고, ppMMA를 게이트 절연층, polymer electret인 ppS를 메모리층으로 한 전계효과트랜지스터 기반 유기 메모리 소자를 제작하였다. 메모리층인 ppS의 두께를 각각 30, 60, 90 nm로 달리한 유기 메모리 소자가 C-V 및 I-V 특성에서 나타내는 히스테리시스 현상을 분석하여 메모리 특성을 평가했으며, 메모리층의 두께 변화에 따른 유기 메모리 소자의 성능을 비교분석하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.545-545
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• 2008

Poly-Si is an essential material for floating gate in NAND Flash memory. To fabricate this material within region of floating gate, chemical mechanical polishing (CMP) is commonly used process for manufacturing NAND flash memory. We use colloidal silica abrasive with alkaline agent, polymeric additive and organic surfactant to obtain high Poly-Si to SiO2 film selectivity and reduce surface defect in Poly-Si CMP. We already studied about the effects of alkaline agent and polymeric additive. But the effect of organic surfactant in Poly-Si CMP is not clearly defined. So we will examine the function of organic surfactant in Poly-Si CMP with concentration separation test. We expect that surface roughness will be improved with the addition of organic surfactant as the case of wafering CMP. Poly-Si wafer are deposited by low pressure chemical vapor deposition (LPCVD) and oxide film are prepared by the method of plasma-enhanced tetra ethyl ortho silicate (PETEOS). The polishing test will be performed by a Strasbaugh 6EC polisher with an IC1000/Suba IV stacked pad and the pad will be conditioned by ex situ diamond disk. And the thickness difference of wafer between before and after polishing test will be measured by Ellipsometer and Nanospec. The roughness of Poly-Si film will be analyzed by atomic force microscope.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.307.2-307.2
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• 2016

In this study, we synthesized Au nanoparticles (AuNPs) in polyacrylonitrile (PAN) thin films using a simple annealing process in the solid phase. The synthetic conditions were systematically controlled and optimized by varying the concentration of the Au salt solution and the annealing temperature. X-ray photoelectron spectroscopy (XPS) confirmed their chemical state, and transmission electron microscopy (TEM) verified the successful synthesis, size, and density of AuNPs. Au nanoparticles were generated from the thermal decomposition of the Au salt and stabilized during the cyclization of the PAN matrix. For actual device applications, previous synthetic techniques have required the synthesis of AuNPs in a liquid phase and an additional process to form the thin film layer, such as spin-coating, dip-coating, Langmuir-Blodgett, or high vacuum deposition. In contrast, our one-step synthesis could produce gold nanoparticles from the Au salt contained in a solid matrix with an easy heat treatment. The PAN:AuNPs composite was used as the charge trap layer of an organic nano-floating gate memory (ONFGM). The memory devices exhibited a high on/off ratio (over $10^6$), large hysteresis windows (76.7 V), and a stable endurance performance (>3000 cycles), indicating that our stabilized PAN:AuNPs composite film is a potential charge trap medium for next generation organic nano-floating gate memory transistors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.799-803
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• 2018

We demonstrated memory thin-film transistors (MTFTs) with organic ferroelectric polymer poly(vinylidene fluoride-co-trifluoroethylene) and an amorphous oxide semiconducting indium gallium zinc oxide channel on the elastomeric substrate. The dielectric constant for the P(VDF-TrFE) thin film prepared on the elastomeric substrate was calculated to be 10 at a high frequency of 1 MHz. The voltage-dependent capacitance variations showed typical butterfly-shaped hysteresis behaviors owing to the polarization reversal in the film. The carrier mobility and memory on/off ratio of the MTFTs showed $15cm^2V^{-1}s^{-1}$ and $10^6$, respectively. This result indicates that the P(VDF-TrFE) film prepared on the elastomeric substrate exhibits ferroelectric natures. The fabricated MTFTs exhibited sufficiently encouraging device characteristics even on the elastomeric substrate to realize mechanically stretchable nonvolatile memory devices.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.212-214
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• 2004

In this study, we fabricated the organic thin film by self-assembly method by using nitro-group and methoxy-group organic molecule. Also, we selected the organic single molecule in organic thin film and measured current-voltage characteristics by using scanning tunneling microscopy. The Organic molecules that use in an experiment is 4,4'-(diethynylphenyl)-2'-nitro-1-benzen ethiol and 4-[2,5-dimethoxy-4-ph enylethynylphenyl]ethynylphenylethanthiol. 4,4'-(dimet hynylphenyl)-2'-nitro-1-benzenethiol is applied widely in molecular electronic device and 4-[2,5-dime thoxy-4-phenylethynylphenyl]ethynylphenylethanthiol composed in Korea Research Institute of Chemical Technology. To be confirmed the formation of the self-assembled monolayers, we observed the real time frequency shift of the QCM and investigated surface of the self-assembled monolayers the using STM. With this, we measured current to the organic single molecule, in condition of the air state. As a result, we confirmed in constant voltage that properties of negative differential resistance. Using properties of negative differential resistance to get from this study, application is expected to be molecular switching device, memory device and logic device.