• Korean Journal of Materials Research
• /
• v.34 no.3
• /
• pp.152-162
• /
• 2024

In this study, we introduce a novel TiN/Ag embedded TiO₂/FTO resistive random-access memory (RRAM) device. This distinctive device was fabricated using an environmentally sustainable, solution-based thin film manufacturing process. Utilizing the peroxo titanium complex (PTC) method, we successfully incorporated Ag precursors into the device architecture, markedly enhancing its performance. This innovative approach effectively mitigates the random filament formation typically observed in RRAM devices, and leverages the seed effect to guide filament growth. As a result, the device demonstrates switching behavior at substantially reduced voltage and current levels, heralding a new era of low-power RRAM operation. The changes occurring within the insulator depending on Ag contents were confirmed by X-ray photoelectron spectroscopy (XPS) analysis. Additionally, we confirmed the correlation between Ag and oxygen vacancies (V_o). The current-voltage (I-V) curves obtained suggest that as the Ag content increases there is a change in the operating mechanism, from the space charge limited conduction (SCLC) model to ionic conduction mechanism. We propose a new filament model based on changes in filament configuration and the change in conduction mechanisms. Further, we propose a novel filament model that encapsulates this shift in conduction behavior. This model illustrates how introducing Ag alters the filament configuration within the device, leading to a more efficient and controlled resistive switching process.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.7
• /
• pp.1159-1164
• /
• 2006

Broadband antennas have late-time ringing by multi-reflections between feed points and 0pen ends of the antennas, which indicates the narrowband nature of the antenna. The resistive loading has been used to reduce the late time ringing that is important for ground penetrating radar and resonance detection systems in order to prevent masking of target. In this paper, we design an ultra wide band antenna with resistive loading technique to reduce the internal reflections within the antenna.. The designed antenna is implemented and tested to show inIproved characteristics.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.359.1-359.1
• /
• 2016

The electromagnetic (EM) properties of media, such as propagation, focusing and scattering, strongly rely on the electric permittivity and the magnetic permeability of media. Recently, artificially-created metamaterials (MMs) composed of periodically-arranged unit cells with tailored electric permittivity and magnetic permeability have drawn wide interest due to their capability of adjusting the EM response. MM absorbers using the conventional sandwich structures usually have very high absorption at a certain frequency, and the absorption properties of MMs can be adjusted simply by changing the geometrical parameters of unit cell. In this work, we suggested an incident-angle-independent broadband perfect absorber based on resistive layers. We analyze the absorption mechanism based on the impedance matching with the free space and the distribution of surface currents at specific frequencies. From the simulation, the absorption was expected to be higher than 96% in 1.4-6.0 GHz. The corresponding experimental absorption was found to be higher than 96% in 1.4-4.0 GHz, and the absorption turned out to be slightly lower than 96% in 4.0-6.0 GHz owing to the irregularity in the thickness of resistive layers.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.298.1-298.1
• /
• 2016

Two-dimensional materials have been received significant interest after the discovery of graphene due to their fascinating electronic and optical properties for the application of novel devices. However, graphene lack of certain bandgap which is essential requirement to achieve high performance field-effect transistors. Analogous to graphene materials, molybdenum disulfide ($MoS_2$) as one of transition-metal dichalcogenides family presents considerable bandgap and exhibits promising physical, chemical, optical and mechanical properties. Here we studied nonvolatile memory based on $MoS_2$ which is grown by chemical vapor deposition (CVD) method. $MoS_2$ growth was taken on $1.5{\times}1.5cm^2$ $SiO_2$/Si-substrate. The samples were analyzed by Raman spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy. Current-voltage (I-V) characteristic was carried out HP4156A. The CVD-$MoS_2$ was analyzed as few layers and 2H-$MoS_2$ structure. From I-V measurement for two metal contacts on CVD-$MoS_2$ sample, we found typical resistive switching memory effect. The device structures and the origin of nonvolatile memory effect will be discussed.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2002.02a
• /
• pp.221-224
• /
• 2002

Superconducting electrical devices are under development in a national project in Korea. And KEPCO and LGIS are in charge of development of a resistive type fault current limiters(FCLs) with YBCO thin films. In order to realize FCLs, the rated power of FCLs must be increased. For this purpose, it is of great interest to increase of allowed voltage of unit component without electrical and thermal damages. So, meander lines were widely used for the conducting path to increase maximum electric field. In this research, numerical simulations on the electromagnetic behaviors of the device were carried out, especially focusing on the effect of meander line structures on the YBCO thin films. To evaluate the structures of meander lines, three types of meander lines were considered for numerical analysis using finite element method (FEM). In this simulation, both normal state and fault conditions were considered for calculation of electric field, current density, magnetic field density. And the simulation resulted are compared to find the optimum design of meander lines for resistive FCLs.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.8 no.3
• /
• pp.15-26
• /
• 1971

The paper presents a new method for analyzing oscillation regions of transistor oscillators. In transistor feedback oscillators oscillation region appears as a circle in feedback impedance complex plane. When the resistive component of feedback impedance is fixed and the reactive component of feedback impedance is varied or vice versa, the locus of maximum negative output conductance becomes hyperbola. In transistor crystal oscillators oscillation region is determined by two circles which make real part and imaginary part of input impedance zero in load impedance complex plane. When the resistive compoment of load impedance is fixed and the reactive colnponent of load impedance is varied or vice versa, the loci of maximum or minimum resistive component of input impedance become straight lines.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.10a
• /
• pp.15.2-15.2
• /
• 2011

비휘발성 저항 메모리소자인 resistance random access memory (ReRAM)는 간단한 소자구조와 빠른 동작특성을 나타내며 고집적화에 유리하기 때문에 차세대 메모리소자로써 각광받고 있다. 현재, 이성분계 산화물, 페로브스카이트 산화물, 고체 전해질 물질, 유기재료 등을 응용한 저항 메모리소자에 대한 연구가 활발히 진행되고 있다. 그 중 ZnO를 기반으로 하는 amorphous InGaZnO (a-IGZO) 박막은 active layer 로써 박막트랜지스터 적용 시 우수한 전기적 특성을 나타내며, 빠른 동작특성과 높은 저항 변화율을 보이기 때문에 ReRAM 에 응용 가능한 재료로써 기대되고 있다. 또한 가시광선 영역에서 광학적으로 투명한 특성을 보이기 때문에 투명소자로서도 응용이 기대되고 있다. 본 연구에서는 indium tin oxide (ITO) 투명 전극을 적용한 ITO/a-IGZO/ITO 구조의 투명 소자를 제작하여 저항 메모리 특성을 평가하였다. Radio frequency (RF) sputter를 이용하여 IGZO 박막을 합성하고, ITO 전극을 증착하여 투명 저항 메모리소자를 구현하였고, resistive switching 효과를 관찰하였다. 또한, 열처리를 통해 a-IGZO 박막 내의 Oxygen vacancy와 같은 결함의 정도에 따른 on/off 저항의 변화를 관찰할 수 있었다. 제작된 저항 메모리소자는 unipolar resistive switching 특성을 보였으며, 높은 on/off 저항의 차이를 유지하였다. Scanning electron microscope (SEM)을 통해 합성된 박막의 형태를 평가하였고, X-ray diffraction (XRD) 및 transmission electron microscopy (TEM)을 통해 결정성을 평가하였다. 제작된 소자의 전기적 특성은 HP-4145 를 이용하여 측정하고 비교 분석하였다.

• Journal of the Korean Society of Safety
• /
• v.33 no.3
• /
• pp.27-32
• /
• 2018

Nowadays, to prevent electrical accidents in Korea, inspectors directly performed checking general electrical facilities as a cycle from every one to three years. It is difficult to presuppose an omen because intact conditions of electrical equipments are not kept at the time of inspection. In this paper, in order to ensure effectiveness of an online basis electric inspection, we developed an electrical safety IoT system using LoRa communication technology to enable monitoring mainly electrical safety components such as overcurrent, overvoltage, resistive leakage current, and power. Then we proposed a method for verifying performances of the prosed electrical safety IoT system. Resistive leakage currents are calculated by using difference of phase between voltages and currents. We verified that average errors are 0.97%, which reference goal is ${\pm}5%$ for a device, through reliability test according to conditions. Results of this research can be used as basic study materials to develop technologies for measuring three phase leakage current and for implementing public electrical safety. platform.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.4
• /
• pp.363-369
• /
• 2005

we compared the operating characteristics between flux-lock type and resistive type superconducting fault current limiters(SFCLs). Flux-lock type SFCL consists of two coils, which are wound in parallel each other through an iron core, and a high-Tc superconducting(HTSC) element is connected with coil 2 in series. The the flux-lock type SFCL can be divided into the subtractive polarity winding and the additive polarity winding operations according to the winding directions between the coil 1 and coil 2. It was confirmed from experiments that flux-lock type SFCL could improve both the quench characteristics and the transport capacity compared to the resistive type SFCL, which means, the independent operation of HTSC element.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.05a
• /
• pp.28.2-28.2
• /
• 2011

Resistance random access memory (ReRAM) is a promising candidate for next-generation nonvolatile memory because of its advantageous qualities such as simple structure, superior scalability, fast switching speed, low-power operation, and nondestructive readout. We investigated the resistive switching behavior of tantalum oxide that has been widely used in dynamic random access memories (DRAM) in the present semiconductor industry. As a result, it possesses full compatibility with the entrenched complementary metal-oxide-semiconductor processes. According to previous studies, TiN is a good oxygen reservoir. The TiN top electrode possesses the specific properties to control and modulate oxygen ion reproductively, which results in excellent resistive switching characteristics. This study presents fully room temperature fabricated the TiN/$TaO_x$/Pt devices and their electrical properties for nonvolatile memory application. In addition, we investigated the TiN electrode dependence of the electrical properties in $TaO_x$ memory devices. The devices exhibited a low operation voltage of 0.6 V as well as good endurance up to $10^5$ cycles. Moreover, the benefits of high devise yield multilevel storage possibility make them promising in the next generation nonvolatile memory applications.