Resistive switching behaviors of a co-sputtered zinc silicate thin film (ZnO and SiO2 targets) have been investigated. We fabricated an Ag/ZnSiOx/highly doped n-type Si substrate device by using an RF magnetron sputter system. X-ray diffraction pattern (XRD) indicated that the Zn2SiO4 was formed by a post annealing process. A unique morphology was observed by scanning electron microscope (SEM) and atomic force microscope (AFM). As a result of annealing process, 50 nm sized nano clusters were formed spontaneously in 200~300 nm sized grains. The device showed a unipolar resistive switching process. The average value of the ratio of the resistance change between the high resistance state (HRS) and the low resistance state (LRS) was about 106 when the readout voltage (0.5 V) was achieved. Resistance ratio is not degraded during 50 switching cycles. The conduction mechanisms were explained by using Ohmic conduction for the LRS and Schottky emission for the HRS.
In this study, we observed current-voltage characteristics of the MIM (metal-insulator-metal) structure. The WOx material was used between metal electrodes as the oxide insulator. The structure of the Al/WOx/TiN shows bipolar resistive switching and the operating direction of the resistive switching is clockwise, which means set at negative voltage and reset at positive voltage. The set process from HRS (high resistance state) to LRS (low resistance state) occurred at - 2.6 V . The reset process from LRS to HRS occurred at 2.78 V . The on/off current ratio was about 10 and resistive switching was performed for 5 cycles in the endurance characteristics. With consecutive switching cycles, the stable Vset and Vreset were observed. The electrical transport mechanism of the device was based on the migration of oxygen ions and the current-voltage curve is following (Ohm``s Law → Trap-Controlled Space Charge Limited Current → Ohm``s Law) process in the positive voltage region.
In this study, we proposed an optical compensation method to improve the symmetricity of contrast ratio for wide viewing angle IPS (in-plane switching) LCD. First, the phase retardation depending on the thickness of compensation film is calculated, and then the phase change is presented at the Poincare sphere. The phase retardation and the polarization state of the light passing through the optical elements are caculated by using the EJMM (extended Jones matrix method). In addition, the transmittance and the contrast countour are also calculated by using the Berremann``s 4x4 matrix method. The simulation is carried out for a IPS LC cell with positive A/C/A compensation film. From the standard deviation of the contrast ratio, we confirmed the symmetricity at each viewing angle is inversely proportional to the standard deviation and calculated the optimum design condition of the uniaxial compensation film for the IPS LCD.
Power semiconductor device has a very long history among semiconductor, since the invention of low-pressure bipolar transistor 1947, and so far from small capacity to withstand voltage-current, high-speed and high-frequency characteristics have been developed with high function. In this study, the PWM IC Switch to the main parts used in IGBT (insulated gate bipolar transistor) for the low power loss and high drive capability of the simulator to Synopsys`` T-CAD used by the 1,700 V NPT Planar IGBT, 1,700 V FS was a study of the Planar IGBT, the results confirmed that IGBT 1,700 V FS Planar is making about 11 percent less than the first designed NPT Planar IGBT.
The resistive switching characteristics of resistive random access memory (ReRAM) based onamorphous Ge0.5Se0.5 thin films have been demonstrated by using Ti/Ag nanocrystals/Ge0.5Se0.5/Ptstructure. Ag nanocrystals (Ag NCs) were spread on the amorphous Ge0.5Se0.5 thin film and they playedthe role of metal ions source. As a result, comparing the conventional Ag/Ge0.5Se0.5/Pt structure, thisTi/Ag NCs/Ge0.5Se0.5/Pt ReRAM device exhibits the highly uniform bipolar resistive switching (BRS)characteristics, such as the operating voltages, and the resistance values. At the same time, a stable DCendurance(> 100 cycles), and the excellent data retention (> 104 sec) properties were found from theTi/Ag NCs/Ge0.5Se0.5/Pt structured ReRAM device.
The bipolar resistive switching characteristics of resistive random access memory (ReRAM) based on HfO2 thin films have been demonstrated by using Ag/HfO2/Pt structured ReRAM device. MIcrowave irradiation (MWI) treatment at low temperature was employed in device fabrication with HfO2thin films as a transition layer. Compared to the as-deposited Ag/HfO2/Pt device, highly improved uniformity characteristics of resistance values and operating voltages were obtained from the MWI treatment Ag/HfO2/Pt ReRAM device. In addition, a stable DC endurance (> 100 cycles) and a high data retention (> 104 sec) were achieved.
Resistance-change Random Access Memory(ReRAM) memory, which utilizes electrochemical control of metal in thin films of solid electrolyte, shows great promise as a future solid state memory. The technology utilizes the electrochemical formation and removal of metallic pathways in thin films of solid electrolyte. Key attributes are low voltage and current operation, excellent scalability, and a simple fabrication sequence. In this work, we investigated the nature of thin films formed by photo doping of Ag+ ions into chalcogenide materials for use in solid electrolyte of Resistance-change RAM devices and switching characteristics according to field-effect.
This paper presents a comparative analysis of the parallel operation of different switches in a DC/DC converter. In high power applications, multi-switch PWM power conditioners may be preferred despite a higher component count, due to the absence of low frequency filters, reduced switching losses and fault tolerance. The paper demonstrates how current sharing (CSH) and time sharing (TSH) lead to the reduction of switching stress in the parallel operation of switches in any converter. The solutions proposed in this study can be applied on different scales to other power conditioners for DC/DC converter systems. Discussions of the concepts, hypotheses and computer simulations are verified by 1 kW experimental results.
In this study, we proposed a novel electrode structure for the fringe field switching (FFS) mode LCD and performed a three-dimensional computer simulation to calculate the optical transmittance for the new structure. In the simulation Erickson-leslie equation and Berreman 4×4 matrix were used for obtaining the director distribution profiles of liquid crystal molecules and the electro-optical characteristics, respectively. Considering the complexity of the motional equation of the liquid crystal molecules, FDM (finite difference method) was used as a numerical method. From the results, We revealed that the light transmission of the newly designed pixel structure is expended to the edge of the pixel electrode. We also confirmed that the light transmittance increased more than 13% compared to that of the conventional electrode structure.