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To control the parasitic conduction between devices, photolithography and dry etching of organic thin-film transistors (OTFTs), which utilize the gate metal as a hard-mask for organic semiconductor (OSC) patterning, are used. This study shows that the hard-mask patterning process results in a gate leakage current, which is attributed to the sidewall defects. The characteristic mechanisms of different leakage currents were studied to understand this behavior, including negative-bias temperature stress (NBTS) testing and measurements of devices with structural asymmetry. Additionally, an optimized structure design is proposed to suppress the leakage and increase the reliability of OTFTs. Such improvements are necessary for practical applications of OTFTs requiring small channel widths, such as displays and logic circuitry. [ABSTRACT FROM AUTHOR]

In this study, an advanced supercritical fluid (SCF) technique that is suitable for materials and electronic devices with low temperature (80 °C) and high pressure (4000 psi) is proposed for a ZnO-based resistive random access memory (RRAM). After an SCF treatment, X-ray photoelectron spectroscopy (XPS) analysis confirms that the concentration of oxygen ions increases in the zinc oxide thin film. Moreover, electrical measurements confirm that the treated ZnO-based random access memory exhibits a lower forming voltage, lower set voltage, and higher ratio of high and low resistance states compared with a device without treatment. Next, the carrier transport mechanism is investigated by fitting the current–voltage curves. Finally, physical models are introduced to illustrate the extra oxygen ions that create better memory characteristics in the random access memory device after the SCF treatment. This significant SCF technique increases the content of oxygen ions without altering the original element ratio and maintains a simple device structure. Thus, the technique shows potential for feasible material improvement capable of effective real applications in the near future. [ABSTRACT FROM AUTHOR]

The HfZrOx (HZO) ferroelectric material is a promising material for ferroelectric memory and is compatible with the semiconductor process for ferroelectric random access memory (FeRAM) and negative capacitance field effect transistor. However, defects often exist in the grain boundary to influence the performance or reliability of devices. In addition, uniformity between devices must be considered when they are mass-produced. Therefore, the grain size will become important in determining the performance and reliability. In this study, we use electrical measurements of current–voltage, capacitance–voltage, and polarization–voltage measurements to test high- and low-temperature deposition devices, with a transmission electron microscope (TEM) image to confirm the grain size. Finally, we propose a model to explain the phenomenon and provide a method to obtain better ferroelectric memory. [ABSTRACT FROM AUTHOR]

This study investigates an improvement in memory characteristics through depositing an In2O3 layer as an oxygen ion reservoir in the switching layer (SL) of resistive random access memory (RRAM). The deposition of In2O3, denoted as Pt/HfO2/In2O3/TiN device, provides better memory characteristics including lower forming voltage (VF), set/reset voltage (VSET/VRESET), larger memory window, and higher resistances with higher uniformity at low resistance state (LRS) and high resistance state (HRS), compared to the devices without the In2O3 deposition, denoted as Pt/HfO2/TiN device. The conduction mechanisms, verified through fitting current–voltage (I - V) curves, are consistent with the results of a varied temperature I - V experiment. Finally, a physical model is proposed to explain our observations. [ABSTRACT FROM AUTHOR]

This research investigates one of the process or element doping methods used to enhance the reliability of resistive random access memory (RRAM). A supercritical fluid process combines the advantages of the high permeability of gas with the solubility of liquids, and this novel process introduces water molecules into the supercritical fluid for oxidation in order to improve the resistance of random storage. In terms of reliability of the memory, while previous research has used an oxygen plasma treatment to improve RRAM device performance, this work performed a comparison of the two methods and found that the supercritical oxidation treatment can reduce the forming voltage by 25% and produce superior electrical operation, with an endurance test exhibiting an increase to 108 cycles and an improvement of 102. The material analysis confirmed that, during the resistance switching process, the switching layer was more oxidized after this novel supercritical oxidation, resulting in the reduction of operating current and improved reliability compared with the plasma oxidation device. [ABSTRACT FROM AUTHOR]

This letter investigates Au30Ag70 (alloy electrode)/SiO2/TiN conductive-bridge random access memory (CBRAM) to verify the influence of ambient conditions on forming voltage ($\text{V}_{\textsf {F}}$) and the location of galvanic reaction. Previous literature demonstrates that the galvanic reaction in CBRAM with an alloy electrode results in a lower $\text{V}_{\textsf {F}}$. In this work, a higher environmental H2O concentration results in a decrease in $\text{V}_{\textsf {F}}$. From this change in $\text{V}_{\textsf {F}}$ , we infer that environmental H2O concentration influences the amount of galvanic reaction. Moreover, we verify the location of the galvanic reaction by varying electrode thickness. Finally, we propose a physical model to explain our observations. [ABSTRACT FROM AUTHOR]

In this letter, we determine the importance of the electrical field distribution and strength during the switching process by demonstrating different trends in the degree of reset and the reset pulse time. In general, a longer reset pulse time results in a higher reset energy; a higher reset energy leads to a higher degree of reset, which we obtained by applying different width square waves. But quite notably, the opposite result was obtained using triangle waves, where a higher degree of reset occurred with a shorter rising time and lower reset energy. We believe that this is due to the electric field effect: if the voltage rises faster than the filament oxidation, the device can produce a larger effective electric field and a higher resistance in the reset process. To further investigate the mechanism, the procedure of the reset process was analyzed in detail, and COMSOL simulation is also carried out for confirmation. [ABSTRACT FROM AUTHOR]

A novel leaky-wave slot antenna for broadside circularly polarized (CP) radiation is presented. The antenna simply consists of a slotline for the feed, an exponentially tapered slot for the radiator, and a shaped end for the terminator. Separating the feed from the curved radiating slot makes the presented antenna unique in design and compact in size. The resulting antenna yields inherent broadband characteristics of leaky-wave antennas on the input impedance, axial ratio (AR), and radiation gain. Particularly, to solve the tilt-beam problem commonly seen in leak-wave antennas, we proposed an extended dual-slot design that successfully achieved the pattern stability over a wide bandwidth. An antenna module with a reflector for unidirectional pattern applications was also developed. The measured performances of the final prototype were found to exhibit 10-dB return loss bandwidth of 40%, 3-dB AR bandwidth of 53%, and half-power gain bandwidth of 59% with CP gain level about 8 dBic. The measured and simulated results were well consistent with each other. [ABSTRACT FROM PUBLISHER]

A compact sequential-phase (SP) feed for circularly polarized sequential-rotation (SR) arrays is presented. Unlike traditional SP feed using multiple segments for impedance transformations, the presented SP feed employs only a single-stage transition where the transmission line width is uniform, making the whole SP feed very compact and neat in layout. The radial design of SP-feed lines to antenna elements may further facilitate the optimization work in adjusting the element spacing. Two miniature square SP feeds of the sizes \lambdag/4 and 3 \lambdag/8 are given and compared. Experimental prototypes were built and verified with measured results. The proposed compact SP feed can be extended to 2^N\times 2^N feeding networks, and is very suitable for large-scale printed CP arrays. [ABSTRACT FROM PUBLISHER]

A 56 to 66 GHz sub-harmonic resistive mixer using 0.13 \mum CMOS technology is presented in this letter. This mixer exhibits a flat conversion loss of about -12 and -13 dB and good isolations between ports from 56 to 66 GHz for both down and up-conversion with a lowest LO power of 0 and -1 dBm. The 2LO-RF isolation is more than 27 dB even if IF input power exceeds 4 dBm, which results from the mechanism of connecting drain and body of the device. Besides, this mixer has a relatively high input P1\ dB and a 3 GHz IF bandwidth in each band defined in IEEE 802.15.3c standard. [ABSTRACT FROM PUBLISHER]